Kawakawa

Piper excelsum G. Forst.

Common & Folk Names

• Kawakawa
• New Zealand Pepper Tree
• Maori Pepper Tree
• Horopito (historical confusion with Pseudowintera colorata)
• Kawa (shortened traditional name)

Plant Family

Piperaceae (Pepper family)

Geographic Location

Kawakawa is endemic to Aotearoa New Zealand, occurring naturally throughout the North Island and the northern and eastern parts of the South Island, extending as far south as Banks Peninsula and Greymouth. It is most abundant in coastal and lowland areas but can be found up to 600 metres elevation. The plant thrives in the warm temperate to subtropical climate zones of New Zealand and is increasingly cultivated in gardens throughout the country for both ornamental and medicinal purposes.

Habitat

Kawakawa grows naturally in regenerating bush, forest margins, coastal scrubland, and shaded areas under mature forest canopy. It prefers moist, sheltered environments and is often found along stream banks, in gullies, and at forest edges where it receives dappled sunlight. As a pioneer species, kawakawa readily colonises disturbed areas and plays an important role in native forest regeneration. The plant is notably frost-tender when young but becomes more cold-hardy with maturity, though it remains sensitive to severe or prolonged frosts.

Growing Conditions

Sun: Partial shade to dappled sunlight is ideal; tolerates full shade but grows more vigorously with some direct sun. Young plants need protection from hot afternoon sun.

Soil: Prefers rich, well-drained, moisture-retentive soil with high organic matter content. Thrives in slightly acidic to neutral pH (5.5-7.0). Tolerates a range of soil types from sandy loam to clay loam but performs best in humus-rich forest-type soils.

Propagation: Easily propagated from semi-hardwood cuttings taken in autumn or early spring (strike rate 70-90% in well-drained potting mix with humidity). Can also be grown from fresh seed collected from ripe orange fruits, though germination is slower and more variable. Remove fleshy fruit coating before sowing seeds.

Care: Keep soil consistently moist, especially during establishment (first 1-2 years). Mulch around the base with organic matter to retain moisture and suppress weeds. Protect young plants from frost and strong winds. Once established, kawakawa is relatively low-maintenance and drought-tolerant. Benefits from annual application of compost or well-rotted manure. Prune lightly after fruiting to maintain shape if desired.

NZ Planting Calendar

Propagation (cuttings): Autumn or early spring (March–May or August–September) – semi-hardwood cuttings, 70-90% strike rate

Sowing (seeds): Spring (September–November) – collect ripe orange fruits, remove fleshy coating before sowing

Planting: Spring (August–October) for best establishment

Flowering: Late spring/summer (November–February)

Fruiting: Summer/autumn (January–April) – orange fleshy fruit clusters on female plants

Harvest (leaves): Year-round; late summer to early autumn (February–March) traditionally considered optimal for volatile oil content

Note: Endemic NZ native; frost-tender when young; prefers partial shade and moist, humus-rich soil; grows 1-3m (occasionally to 6m)

Harvesting Guidelines

Harvest kawakawa leaves from healthy, mature plants during late summer to early autumn (February-March) when volatile oil content is traditionally considered highest, though leaves can be harvested year-round. In rongoā Māori tradition, leaves with holes from the kawakawa looper moth (Cleora scriptaria) are particularly valued—the belief is that the plant concentrates its healing energy where it has been “tested” by the caterpillar. Select 2-3 leaves maximum from any single plant to ensure plant vitality and regeneration. Choose mature leaves from the middle section of stems rather than tender new growth or old yellowing leaves. Harvest in the morning after dew has dried but before the heat of midday, which can volatilise essential oils. If harvesting for drying, select unblemished leaves; if using fresh for topical preparations, holey leaves are traditional and acceptable. Always harvest with respect and consideration, offering thanks (karakia) if this aligns with your practice, and leave abundant foliage for plant regeneration, insects, and native birds that feed on the fruits.

Parts Used

• Leaves (primary medicinal part)
• Roots (traditionally used in rongoā Māori by practitioners with appropriate cultural knowledge)
• Fruits (occasionally, for specific traditional applications)

Constituents & their Actions

Kawakawa contains over 60 identified biologically active compounds that contribute to its diverse therapeutic effects. The phytochemical profile varies with season, location, plant maturity, and growing conditions. The most abundant and pharmacologically significant constituents fall into four main categories:

Phenylpropanoids:

Phenylpropanoids are aromatic compounds derived from the amino acid phenylalanine and are responsible for much of kawakawa’s characteristic peppery aroma and medicinal activity. Some of the main phenylpropanoids in kawakawa are:

• Myristicin (most abundant in essential oil, 2-5% of total volatile compounds)
• Elemicin (second most abundant phenylpropanoid)
• Apiole (present in smaller quantities)

The main actions of these phenylpropanoids are:

• Analgesic effects: Myristicin and elemicin modulate pain signalling pathways through multiple mechanisms, including inhibition of prostaglandin synthesis and interaction with opioid receptors, which in turn reduces pain perception and provides relief from toothache, muscular aches, and general discomfort.
• Anti-inflammatory activity: These compounds reduce production of pro-inflammatory cytokines including interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-α), and nitric oxide (NO), which in turn decreases inflammation in tissues affected by conditions such as eczema, psoriasis, digestive inflammation, and arthritic pain.
• Antimicrobial properties: Phenylpropanoids disrupt bacterial and fungal cell membranes and interfere with microbial metabolism, which in turn provides protection against wound infections and supports traditional use for cuts, boils, and skin infections.
• Metabolic effects: Research shows phenylpropanoids may influence glucose metabolism and insulin sensitivity through modulation of cellular signalling pathways, which in turn may help regulate blood sugar levels.

Lignans:

Lignans are polyphenolic compounds formed from the coupling of phenylpropanoid units. Kawakawa contains several unique lignan compounds. Some of the main lignans in kawakawa are:

• Yangambin (also called (+)-yangambin or diayangambin)
• (+)-Excelsin
• Diayangambin derivatives

The main actions of these lignans are:

• Cardiovascular anti-inflammatory effects: Yangambin has been shown in human trials to reduce inflammatory markers in the cardiovascular system by modulating endothelial function and reducing oxidative stress, which in turn may support heart health and reduce systemic inflammation.
• Immunomodulatory activity: These lignans possess immunosuppressant properties that help regulate overactive immune responses, which in turn may be beneficial for autoimmune conditions such as rheumatoid arthritis and psoriasis where the immune system attacks the body’s own tissues.
• Antioxidant effects: Lignans act as free radical scavengers, protecting cells from oxidative damage, which in turn supports overall cellular health and may slow the progression of inflammatory skin conditions.

Amides (Piperine-related compounds):

Amides are nitrogen-containing compounds structurally related to piperine found in black pepper. Kawakawa contains numerous amide compounds. The main amides in kawakawa are:

• Pellitorine (the most abundant compound overall in kawakawa leaves)
• Fagaramide
• Piperchabamide A
• Piperdardine
• Piperine
• Dihydropiperlonguminine

The main actions of these amides are:

• Numbing and analgesic effects: Pellitorine produces local anaesthetic-like sensations on mucous membranes and skin by temporarily reducing nerve sensitivity, which in turn explains traditional use for toothache relief when leaves are chewed and provides immediate pain relief for oral pain, mouth ulcers, and sore throat.
• Anti-inflammatory pathway modulation: Amides inhibit key inflammatory enzymes including cyclooxygenase (COX) and lipoxygenase (LOX), which in turn reduces production of inflammatory mediators and provides relief from both acute and chronic inflammation.
• Digestive support: These compounds have antispasmodic effects on smooth muscle in the gastrointestinal tract, relaxing intestinal cramping and easing digestive discomfort, which in turn makes kawakawa valuable for nervous indigestion, stomach aches, and digestive upset.
• Enhanced bioavailability: Piperine-related amides inhibit certain drug-metabolising enzymes and increase intestinal permeability, which in turn can enhance absorption of other beneficial compounds including curcumin from turmeric, vitamins, and phytonutrients.
• Metabolic effects: Research demonstrates that kawakawa amides increase glucose uptake and decrease fatty acid uptake in intestinal cells, which in turn may support healthy metabolic function and blood sugar regulation.

Flavonoids and other compounds:

Kawakawa also contains flavonoid glycosides and other bioactive compounds. Some of the main additional constituents in kawakawa are:

• Vitexin (flavone glycoside)
• Isovitexin (flavone glycoside)
• Dopamine (neurotransmitter, does not cross blood-brain barrier)
• Trigonelline (alkaloid)
• Sesquiterpenes (α-Pinene, camphene, aromadendrene, γ-Cadinene)

The main actions of these compounds are:

• Additional anti-inflammatory effects: Flavonoids like vitexin and isovitexin reduce TNF-α production and modulate inflammatory gene expression, which in turn provides complementary anti-inflammatory activity to the other constituents.
• Digestive effects: Dopamine, while not crossing the blood-brain barrier when consumed orally, has known beneficial effects on gastrointestinal motility and function, which in turn may contribute to kawakawa’s traditional use for digestive complaints.
• Antimicrobial activity: Sesquiterpenes contribute to the plant’s antimicrobial and antifungal properties, which in turn support use for wound healing and skin infections.
• Antioxidant protection: Multiple compounds provide free radical scavenging activity, which in turn protects tissues from oxidative damage and supports overall health.

Actions with Mechanisms

Analgesic (Pain Relief):
Kawakawa provides pain relief through multiple synergistic mechanisms. Myristicin and elemicin modulate pain signalling by inhibiting cyclooxygenase (COX) enzymes, which reduces prostaglandin synthesis, which in turn decreases pain and inflammation. Additionally, these phenylpropanoids may interact with opioid receptors in peripheral tissues, potentiating pain relief without central nervous system effects. Pellitorine, the most abundant compound in kawakawa, produces a distinctive numbing sensation by temporarily reducing nerve conductivity in sensory neurons, which in turn provides immediate localised pain relief. This explains the traditional practice of chewing fresh leaves for toothache, where the direct application of pellitorine to oral tissues produces rapid analgesic effects. The combined action of these multiple analgesic compounds makes kawakawa effective for various types of pain including dental pain, muscular aches, arthritic discomfort, and neuralgic pain.

Anti-inflammatory:
Kawakawa demonstrates potent anti-inflammatory activity through multiple biochemical pathways. Myristicin inhibits the production of pro-inflammatory cytokines including interleukin-6 (IL-6), interleukin-10 (IL-10), and nitric oxide (NO) in macrophages and monocytes by interfering with inflammatory signalling cascades, which in turn reduces systemic and localised inflammation. Recent human clinical research shows that kawakawa consumption modulates the expression of multiple microRNAs (miRNAs) that regulate inflammatory gene expression, leading to both upregulation of anti-inflammatory pathways and downregulation of pro-inflammatory responses, which in turn produces a balanced immunological effect. Lignans such as diayangambin exert immunosuppressant effects by modulating T-cell activity and reducing production of inflammatory mediators, which in turn helps control overactive immune responses seen in autoimmune conditions like rheumatoid arthritis and psoriasis. The amide compounds inhibit both COX and LOX inflammatory enzymes, which in turn blocks production of prostaglandins and leukotrienes that drive inflammation in tissues. This multi-targeted anti-inflammatory activity explains kawakawa’s effectiveness for both internal inflammation (digestive, respiratory) and external inflammatory conditions (eczema, dermatitis, swollen joints).

Digestive Support and Spasmolytic:
Kawakawa has well-established traditional use for digestive complaints, supported by its constituent profile. The amide compounds, particularly pellitorine, exert antispasmodic effects on smooth muscle in the gastrointestinal tract by inhibiting calcium influx into muscle cells, which in turn relaxes intestinal cramping and eases digestive spasms. The bitter principles in kawakawa stimulate digestive secretions including gastric acid, bile, and pancreatic enzymes through activation of bitter taste receptors on the tongue and in the gut, which in turn improves digestion and nutrient absorption. Dopamine, present in significant quantities in kawakawa leaves, acts on dopamine receptors in the enteric nervous system (the “gut brain”), which in turn influences gastric motility and may help regulate gut function. The plant’s gentle warming energetics stimulate circulation to digestive organs, which in turn enhances digestive efficiency and relieves sensations of cold or stagnation in the abdomen. Kawakawa’s combined carminative, antispasmodic, and bitter properties make it valuable for various digestive issues including nervous indigestion, stomach aches from overeating, intestinal cramping, bloating, and general digestive sluggishness.

Antimicrobial and Wound Healing:
Kawakawa demonstrates broad-spectrum antimicrobial activity against bacteria and fungi, supporting its extensive traditional use for skin infections and wounds. The phenylpropanoids (myristicin, elemicin) and sesquiterpenes disrupt microbial cell membranes through lipophilic interactions, which increases membrane permeability and causes leakage of cellular contents, which in turn kills or inhibits the growth of pathogenic organisms. Laboratory studies show activity against various bacterial strains including Staphylococcus aureus and Escherichia coli, as well as antifungal activity against Candida species and dermatophytic fungi. The lignans provide additional antimicrobial effects while also reducing inflammation at wound sites, which in turn creates an optimal environment for tissue regeneration. Kawakawa’s astringent tannins help constrict blood vessels and form a protective layer over damaged tissue, which in turn reduces bleeding and protects against microbial invasion. The combined antimicrobial, anti-inflammatory, and vulnerary properties make kawakawa particularly effective for cuts, scrapes, boils, infected wounds, fungal skin infections, and slow-healing wounds. Fresh or dried leaves can be applied as poultices, or infused oils can be used topically to deliver therapeutic compounds directly to affected areas.

Diaphoretic (Promotes Sweating):
Kawakawa functions as a warming diaphoretic, promoting perspiration and supporting the body’s natural fever response during acute infections. The combination of warming aromatics (sesquiterpenes) and vasodilatory compounds stimulates peripheral blood circulation, which brings blood to the skin surface, which in turn facilitates heat dissipation through increased perspiration. This diaphoretic action helps the body release metabolic waste products and pathogens through the skin, which in turn supports detoxification and immune function during colds, flu, and other acute infections. Hot infusions of kawakawa leaves produce a particularly pronounced diaphoretic effect, making them traditional remedies for breaking fevers and supporting recovery from winter ailments. The warming nature also helps expel cold from the body, which in turn relieves symptoms of cold and dampness such as chills, cold extremities, and respiratory congestion.

Nervine (Gentle Calming):
While not a primary action, kawakawa possesses mild nervine properties. The plant contains trace amounts of compounds structurally similar to those found in kava (Piper methysticum), including dihydrokawain and kawain, though in much lower concentrations. These compounds may interact with GABA receptors in the central nervous system, producing subtle calming and anxiolytic effects, which in turn may help ease nervous tension and stress-related digestive complaints. Traditional use suggests kawakawa has gently uplifting yet calming properties, helping to ease nervous agitation while maintaining mental clarity. The warming, aromatic nature of the plant also has grounding and centring qualities appreciated in traditional medicine. While kawakawa should not be considered a strong nervine like valerian or passionflower, its subtle calming effects complement its digestive and anti-inflammatory actions, making it particularly useful for stress-related digestive upset and nervous stomach.

Metabolic Support:
Emerging research demonstrates that kawakawa may support healthy metabolic function. Human clinical trials show that acute consumption of kawakawa tea modulates postprandial (after-meal) microRNA expression in ways that influence glucose and lipid metabolism, which in turn may help regulate blood sugar and fat metabolism. In vitro studies demonstrate that piperine-related amides in kawakawa increase glucose uptake in intestinal cells while decreasing fatty acid uptake, which in turn may influence nutrient absorption patterns beneficially. The plant’s effects on inflammatory pathways may also indirectly support metabolic health, as chronic inflammation is closely linked to metabolic dysfunction. While more research is needed to fully understand these effects, traditional use of kawakawa as a general tonic and the emerging scientific evidence suggest potential benefits for metabolic health and blood sugar regulation.

Main Use

Kawakawa’s primary therapeutic applications reflect its dual nature as both an internal remedy and topical healing agent. Internally, kawakawa is most commonly used for digestive support, particularly for nervous indigestion, stomach aches from overeating, intestinal cramping, bloating, and general digestive upset. The plant’s combination of bitter, carminative, antispasmodic, and warming properties makes it an excellent gentle digestive tonic suitable for daily use. Traditional use includes respiratory support during colds, flu, and bronchial congestion, where kawakawa’s diaphoretic and antimicrobial properties help the body mount an effective immune response and clear infection. As a general tonic, kawakawa provides gentle stimulation and rejuvenation, supporting overall vitality without being overstimulating—early European settlers even substituted kawakawa leaves for tea due to their refreshing and sustaining properties.

Topically, kawakawa is renowned as one of New Zealand’s premier wound healing and skin-soothing herbs. It excels at treating inflammatory skin conditions including eczema, psoriasis, dermatitis, and various rashes, where its anti-inflammatory, antimicrobial, and soothing properties work synergistically to reduce itching, inflammation, and infection risk while promoting healing. Kawakawa is traditional first-aid for minor cuts, scrapes, burns, boils, and infected wounds, with the leaves applied fresh as poultices or used as infused oils and balms. The plant’s numbing analgesic properties make it valuable for insect bites and stings, providing rapid relief from pain, itching, and swelling. Its effectiveness for rheumatic pain, sore muscles, and joint inflammation—applied topically or taken internally—reflects the plant’s systemic anti-inflammatory and analgesic actions. The traditional practice of chewing fresh leaves for toothache remains effective due to pellitorine’s potent numbing effects on oral tissues.

Preparations

Fresh Leaf Infusion (Tea): Place 2-3 fresh kawakawa leaves (or 1-2 teaspoons dried leaves) in a cup and cover with boiling water. Cover the cup to retain volatile oils and steep for 10-15 minutes. Strain and drink warm. Fresh leaves produce a more aromatic, peppery tea; dried leaves offer a milder, slightly bitter flavour. For digestive support, drink 1 cup 2-3 times daily, particularly after meals or when experiencing digestive discomfort. For respiratory support during acute illness, drink hot infusions 3-4 times daily to promote diaphoresis (sweating) and support immune function.

Decoction (Stronger Internal Use): For more persistent conditions or when stronger medicine is needed, use 3-4 fresh leaves (or 2 teaspoons dried) per cup of water. Bring water and herbs to a boil, then reduce heat and simmer gently, covered, for 10-15 minutes. Strain and drink warm. This preparation extracts more of the plant’s constituents, particularly lignans and less volatile compounds. Use for chronic digestive issues, persistent inflammation, or as a warming tonic during recovery from illness. Drink ½ to 1 cup 2-3 times daily.

Tincture (Alcohol Extract): Fresh or dried leaves can be tinctured for long-term storage and convenience. Use a 1:5 ratio of fresh herb to menstruum (100g fresh leaves to 500ml liquid) or 1:5 ratio for dried herb (100g dried leaves to 500ml liquid). For fresh plant tincture, use 40-50% alcohol (vodka or brandy work well); for dried plant, use 50-60% alcohol. Finely chop fresh leaves and place in a clean glass jar, cover with alcohol menstruum, and steep for 3-4 weeks, shaking daily. Strain and bottle. Dosage: 2-4ml (40-80 drops) in water, 2-3 times daily for digestive support or general tonic use. Tincture captures both volatile and resinous constituents effectively.

Infused Oil (Topical Base): Traditional folk method: Fill a clean, dry glass jar 2/3 full with dried kawakawa leaves (or wilted fresh leaves dried for 12-24 hours to reduce water content). Cover completely with carrier oil such as olive oil, sweet almond oil, or sunflower oil. Ensure all plant material is submerged to prevent mould. Place jar in a sunny windowsill and leave for 4-6 weeks, shaking daily. Strain through muslin, squeezing out all oil. For faster preparation, use the heat method: Place herb and oil in a double boiler or slow cooker on lowest setting and infuse for 4-8 hours, maintaining temperature around 40-50°C. Strain. Infused oil can be used directly on skin for eczema, psoriasis, dry skin, minor wounds, insect bites, or arthritic joints. Can also be used as the base for making balms and salves.

Kawakawa Balm (Topical Salve): To make a healing balm, melt 100ml kawakawa-infused oil with 10-15g beeswax (adjust beeswax amount for desired consistency—more for firmer balm, less for softer). Add 5-10 drops mānuka essential oil (optional but traditional in NZ preparations) for enhanced antimicrobial properties. Pour into small tins or jars while warm and allow to solidify. This balm is excellent for eczema, psoriasis, cuts, scrapes, burns, insect bites, cracked lips, dry skin, and as a general healing salve. The beeswax provides a protective barrier while the infused oil delivers kawakawa’s medicinal compounds directly to affected tissues. Apply as needed, 2-4 times daily for active conditions, or as desired for general skin care.

Fresh Leaf Poultice (Traditional First Aid): For immediate first aid application, crush or chew 1-2 fresh kawakawa leaves to release their juices and break down cell walls. Apply the macerated leaves directly to the affected area—cuts, insect bites, stings, minor burns, or to the gums and cheek for toothache. Hold in place with a bandage if needed. For toothache specifically, chew a fresh leaf and hold the masticated material against the painful tooth and surrounding gum, allowing the pellitorine to numb the area. Replace with fresh leaf material every 30-60 minutes as needed. This traditional method provides rapid pain relief and antimicrobial protection at wound sites.

Strong Infusion for Topical Wash: Make a strong tea using 4-6 fresh leaves (or 2-3 tablespoons dried leaves) per cup of boiling water. Steep covered for 15-20 minutes, then strain and allow to cool to a comfortable temperature. Use as a wash or compress for eczema, psoriasis, fungal infections, wounds, cuts, or inflammatory skin conditions. Apply 2-3 times daily using a clean cloth or cotton pad, or add 2-3 cups of strong infusion to a bath for full-body skin soothing. For wound care, ensure the infusion has cooled adequately and use clean application techniques to avoid introducing contamination.

Dosage

Fresh Leaf Tea: 2-3 fresh leaves per cup, 1-3 cups daily. Particularly effective when consumed after meals for digestive support.

Dried Leaf Tea/Infusion: 1-2 teaspoons dried leaves per cup, steeped 10-15 minutes. Drink 1-3 cups daily for internal use. For respiratory support during acute illness, drink 3-4 cups daily of hot infusion.

Decoction (Stronger preparation): 3-4 fresh leaves or 2 teaspoons dried leaves per cup, simmered 10-15 minutes. Drink ½ to 1 cup, 2-3 times daily for chronic conditions.

Tincture (1:5, 40-60% alcohol): 2-4ml (40-80 drops) in water, 2-3 times daily for internal use as digestive support, general tonic, or anti-inflammatory support.

Topical Use—Infused Oil: Apply directly to affected skin 2-4 times daily for eczema, psoriasis, wounds, insect bites, sore muscles, or arthritic joints. Massage gently into affected areas.

Topical Use—Balm/Salve: Apply as needed, typically 2-4 times daily for active inflammatory conditions, wounds, or skin irritations. Can be used more frequently for lip care or minor skin protection.

Topical Wash: Strong infusion (4-6 leaves per cup) applied to affected areas 2-3 times daily with clean cloth or cotton pad, or added to baths (2-3 cups per bath).

Fresh Leaf Poultice: Apply freshly crushed leaves directly to affected area, replacing every 30-60 minutes as needed for acute pain or wound care.

Safety & Drug Interactions

Scientific Evidence

Anti-inflammatory Effects in Humans: A 2024 randomised controlled trial published in Food Science & Nutrition (Tautuiaki et al.) demonstrated that acute consumption of kawakawa tea modulated postprandial microRNA expression in healthy adults, affecting inflammatory pathways. The study found both upregulation of some anti-inflammatory miRNAs (hsa-miR-17-5p, -21-5p, -320a-5p, let-7g-5p, -16-5p, -122-5p, -144-3p) and downregulation of others (hsa-miR-221-3p, -223-3p), suggesting kawakawa helps regulate balanced inflammatory responses at the molecular level.

Glucose Metabolism Effects: Research by Ramzan et al. (2022) published in Nutrients investigated kawakawa’s effects on postprandial glucose and insulin response in healthy volunteers. While the study did not find significant changes in overall glucose or insulin curves, metabolomic profiling identified key active compounds (myristicin, elemicin, yangambin, fagaramide, pellitorine) in participants’ plasma, confirming bioavailability and metabolism of kawakawa’s medicinal compounds following tea consumption.

Comprehensive Phytochemical Profiling: A 2022 study in Nutrients (Butts et al.) used advanced liquid chromatography-mass spectrometry to identify more than 60 biologically active compounds in kawakawa leaves, including phenylpropanoids, lignans, amides, flavonoids, alkaloids, and the neurotransmitter dopamine. This research quantified major constituents and documented significant variation based on leaf source, harvest time, and growing conditions, validating traditional knowledge about leaf selection and harvest timing.

Safety Evaluation: Butts et al. (2019) published safety evaluation of kawakawa tea in rats in the Journal of Ethnopharmacology. The 14-day acute study and 28-day subacute study found no adverse effects at doses equivalent to 1-4 cups of tea daily in humans, with no significant changes in body weights, food intake, organ weights, biochemical parameters, or haematological values, supporting the safety of traditional therapeutic use.

In Vitro Antimicrobial Activity: Multiple laboratory studies have demonstrated antimicrobial activity of kawakawa extracts against various pathogenic bacteria and fungi. While specific MIC (minimum inhibitory concentration) values vary between studies, consistent activity has been shown against common pathogens including Staphylococcus aureus, Escherichia coli, and Candida albicans, supporting traditional use for infected wounds and skin conditions.

Analgesic Activity in Animal Models: Animal studies have demonstrated analgesic effects of myristicin and related compounds through modulation of pain signalling pathways and prostaglandin synthesis, providing mechanistic support for traditional use of kawakawa for pain relief including toothache, muscular pain, and general discomfort.

Evidence Level: Strong traditional use over centuries providing extensive observational evidence; Growing laboratory evidence demonstrating biological activity of isolated compounds and whole-plant extracts; Emerging human clinical research confirming bioavailability and preliminary health effects; Limited large-scale randomised controlled trials. This evidence pattern is typical for indigenous medicines where lack of clinical trials reflects lack of research funding rather than lack of efficacy. The combination of centuries of traditional use, mechanistic laboratory research, and emerging human trials provides a robust foundation supporting kawakawa’s therapeutic applications.

Western Energetics

Temperature: Warming. Kawakawa has distinctly warming properties that stimulate circulation, promote sweating, and help expel cold from the body. The peppery, aromatic volatile oils produce a sensation of warmth when consumed or applied topically, making kawakawa particularly appropriate for cold conditions, poor circulation, cold extremities, respiratory infections with chills, and digestive sluggishness from cold or deficiency. The warming nature helps move stagnation and improve vitality in individuals who feel cold, tired, or depleted. However, this warming quality means kawakawa should be used judiciously in very hot conditions or for individuals with excessive heat patterns.

Moisture: Neutral to slightly drying. While not strongly drying like some aromatic herbs, kawakawa’s diaphoretic properties can promote fluid loss through sweating, and its stimulating effects may have a subtle drying influence. However, the plant is not considered primarily drying and can be used across a range of moisture states. The slight drying tendency makes it appropriate for damp, boggy conditions with mucus accumulation, poor digestion with heaviness, or weeping skin conditions. For very dry individuals, kawakawa can be combined with more moistening herbs or used with nourishing carriers like infused oils.

Tissue State: Kawakawa addresses multiple tissue states through its diverse actions. Most prominent are: Depression/Atony (tissues that are cold, deficient, stagnant, lacking tone)—kawakawa’s warming, stimulating properties help restore vitality, improve circulation, and energise sluggish systems, making it valuable for chronic fatigue, poor digestion from deficiency, and general depletion. Tension/Constriction—the antispasmodic and analgesic properties help release cramping, tightness, and pain in muscles and digestive tract, addressing patterns of tension and holding. Atrophy/Depletion with Depression—as a gentle tonic, kawakawa helps rebuild strength and vitality over time while immediately stimulating function. Heat/Inflammation—despite being warming in nature, kawakawa’s strong anti-inflammatory properties make it appropriate for inflammatory conditions, particularly when inflammation is present alongside underlying deficiency or when applied topically to inflamed tissues.

Taste

Pungent (Acrid): The primary taste of kawakawa is pungent or acrid, characteristic of the aromatic volatile oils and piperine-related amides. This pungency produces a sharp, warming, somewhat numbing sensation on the tongue and mucous membranes. The pungent taste correlates with kawakawa’s warming, stimulating, and dispersing properties—it moves energy, promotes circulation, breaks up stagnation, and expels pathogens. Pungent taste also stimulates digestive secretions and has expectorant effects for respiratory conditions. The distinctive tingling, slightly numbing quality reflects pellitorine’s anaesthetic action.

Bitter: Beneath the dominant pungency, kawakawa possesses a secondary bitter note that becomes more apparent as the tea cools or with dried leaves. This bitterness reflects the presence of lignans, flavonoids, and other polyphenolic compounds. The bitter taste supports kawakawa’s digestive applications by stimulating bile production, enhancing liver function, and improving overall digestive efficiency. Bitter taste is cooling and drying, providing some balance to the warming pungent qualities.

Slightly Aromatic/Sweet: There is a subtle aromatic, almost slightly sweet quality underneath the primary tastes, particularly noticeable in fresh leaves. This reflects the complex volatile oil profile and adds to the plant’s overall pleasant, though distinctive, flavour. This aromatic quality is what made kawakawa an acceptable tea substitute for early settlers and contributes to its warming, uplifting effects.

The taste profile of kawakawa—predominantly pungent with bitter undertones—directly reflects its therapeutic actions and energetic properties. The pungency drives its warming, stimulating, analgesic, and dispersing effects, while the bitterness supports its digestive and anti-inflammatory actions. Together, these tastes create a medicine that energises, warms, disperses stagnation, stimulates digestion, and clears inflammation—all key aspects of kawakawa’s clinical applications.

Plant Lore

Kawakawa (Piper excelsum) holds a position of profound cultural, spiritual, and medicinal significance in Aotearoa New Zealand as one of the most important plants in rongoā Māori. The name “kawakawa” itself may derive from the word “kawa,” meaning bitter or sour, reflecting the plant’s distinctive taste, or may reference ceremonial protocols (also called kawa), acknowledging the plant’s sacred status. In Māori tradition, kawakawa is recognised as a taonga (treasure), a gift from the atua (spiritual forces) and Tāne Mahuta (the forest guardian), embodying the healing power of the natural world.

Traditional rongoā Māori encompasses far more than the physical medicinal properties of plants—it is a complete healing system integrating spiritual, psychological, and physical dimensions. Kawakawa is central to this system, used not only for its medicinal compounds but also in karakia (prayers and incantations), ceremonial cleansing, and spiritual protection. Tohunga (traditional healers) and kaitiaki (guardians of knowledge) have maintained detailed understanding of kawakawa’s applications across generations through oral tradition, practical apprenticeship, and spiritual connection with the plant. This knowledge includes not only which parts to use for specific conditions but also appropriate harvest protocols, preparation methods, karakia to accompany medicine-making, and understanding of the plant’s wairua (spirit).

The distinctive holes in kawakawa leaves, created by the kawakawa looper moth (Cleora scriptaria), hold special significance in rongoā Māori tradition. Rather than viewing these holes as damage, traditional knowledge recognises leaves with holes as particularly potent medicine. The belief is that the plant’s mauri (life force) becomes concentrated where it has been “tested” by the caterpillar, creating stronger healing properties. This perspective reflects a sophisticated understanding of plant chemical ecology—research now shows that plants often increase secondary metabolite production (including medicinal compounds) in response to herbivore damage as a defence mechanism. This traditional knowledge thus anticipated modern scientific understanding by centuries. Harvesting practices emphasise respect for this relationship between kawakawa and its associated moth, recognising the interconnection between species.

Gender in kawakawa plants is also culturally significant. Kawakawa is dioecious, with separate male and female plants. Female plants bear the distinctive orange, fleshy fruit clusters (drupes) that were part of traditional Māori diet and hold their own medicinal and cultural importance. Male plants produce elongated flowering spikes. Traditional knowledge includes understanding these differences and may involve specific applications or protocols for male versus female plants, though such detailed rongoā knowledge is properly transmitted through direct teaching rather than written sources.

Early European settlers and missionaries in New Zealand quickly recognised kawakawa’s value, learning about the plant from Māori and adopting it into their own medicinal practices. The leaves were commonly used as a tea substitute, particularly appreciated for their stimulating yet soothing qualities and distinctive peppery flavour. Early botanical explorers documented kawakawa extensively, with the scientific names Piper excelsum (named by German botanist Georg Forster) and later Macropiper excelsum reflecting its placement within the global pepper family. The epithet “excelsum” means “tall” or “lofty,” referring to the plant’s growth habit as a shrub or small tree.

Historical medicinal texts from colonial New Zealand document kawakawa’s adoption into European settler medicine for conditions ranging from digestive complaints to rheumatism, toothache to bronchial infections, demonstrating the plant’s versatility and the successful knowledge transfer from Māori to Pākehā (European) communities. This cross-cultural adoption of kawakawa represents one of the more positive aspects of early New Zealand history, where indigenous medicinal knowledge was recognised and valued, though often without proper acknowledgment or respect for its cultural context.

In modern times, kawakawa has experienced a renaissance in both mainstream New Zealand culture and commercial natural health markets. Kawakawa-infused products including teas, balms, oils, soaps, and skincare preparations are widely available and popular among New Zealanders of all backgrounds. This popularity brings both opportunities and responsibilities. There is growing recognition of the need to approach kawakawa with cultural respect, acknowledging its status as a taonga, supporting Māori-owned businesses working with the plant, ensuring sustainable harvesting practices, and understanding that commercial use of kawakawa should benefit and honour the indigenous communities who have been its kaitiaki for centuries.

The kawakawa looper moth deserves special mention in kawakawa lore. This native geometrid moth (Cleora scriptaria) has evolved a specialist relationship with kawakawa—its caterpillars feed almost exclusively on kawakawa leaves, creating the characteristic holes. The adult moths are cryptically coloured to blend with bark and are relatively inconspicuous, but their larvae are easily recognised by their characteristic “looping” movement. Traditional knowledge recognises this moth not as a pest but as part of kawakawa’s whakapapa (genealogy) and identity. The relationship between plant and insect represents the intricate web of connections that characterise healthy ecosystems, and respecting this relationship is part of respectful engagement with kawakawa.

Kawakawa’s story is ultimately one of connection—connection between people and place, between traditional knowledge and modern science, between physical healing and spiritual wellbeing, and between past, present, and future. Working with this plant offers an opportunity to practice respectful, sustainable herbalism that honours indigenous knowledge while making healing medicine accessible to all who approach it with appropriate reverence and gratitude.

Additional Information

Companion Planting: Kawakawa grows well alongside other native New Zealand plants in garden settings, particularly ferns (ponga), flax (harakeke), māhoe, and karamu. It can be used as an understorey plant in native gardens or as part of restoration planting. The plant’s presence supports native biodiversity, providing habitat and food for native moths, geckos, and birds that feed on the fruits.

Identification Tips for Foragers: Kawakawa is relatively easy to identify due to its distinctive heart-shaped leaves, which are aromatic when crushed with a peppery scent. The leaves have prominent veining and a slightly rough, textured surface. Stems are jointed with noticeable nodes (characteristic of Piperaceae family). Female plants bear orange fleshy fruit clusters; male plants have elongated flowering spikes. The plant’s growth habit as a multi-stemmed shrub reaching 1-3 metres (occasionally to 6 metres) in sheltered locations is distinctive. Most importantly, the characteristic holes from kawakawa looper moth provide a strong identification feature, though not all kawakawa leaves will have holes.

Conservation Considerations: While kawakawa is not threatened and is actually common throughout much of its range, sustainable harvesting practices remain important. In urban areas where kawakawa is planted ornamentally, always obtain permission before harvesting. In native bush, be particularly conservative with harvesting, taking only 2-3 leaves per plant and leaving abundant foliage. Never harvest from rare or isolated plants, and be aware of any local conservation areas where plant material removal is prohibited. Consider growing your own kawakawa rather than relying solely on wild-harvesting—the plant is relatively easy to cultivate and thrives in many garden situations.

Quality Considerations: For medicinal use, the highest quality kawakawa comes from healthy plants growing in clean, unpolluted environments with minimal human disturbance. Leaves harvested in late summer (February-March) are traditionally considered most potent, though leaves can be collected year-round. Fresh leaves are generally preferred for immediate use and fresh preparations, while properly dried leaves retain medicinal properties for tea and tincture making. When drying, spread leaves in a single layer in a warm, dark, well-ventilated space (not in direct sun, which can degrade volatile oils). Properly dried leaves should retain some green colour and aromatic scent; brown, odourless leaves indicate over-oxidation and reduced quality. Store dried kawakawa in airtight containers away from light, heat, and moisture; properly stored dried leaves maintain quality for 6-12 months.

Wildcrafting Ethics: When harvesting kawakawa from the wild, practice respectful wildcrafting ethics: never take more than 5-10% of available foliage from an area; spread your harvest across many plants rather than taking heavily from few; leave the healthiest, most vigorous specimens unharvested to provide seed for the next generation; avoid harvesting during flowering and fruiting if possible to allow plants to complete reproductive cycles; watch for signs of over-harvesting in popular areas and avoid adding additional pressure to stressed plant populations. Remember that native birds, insects, and other wildlife depend on kawakawa for food and habitat.

Combinations with Other New Zealand Natives: In rongoā Māori tradition, kawakawa is often combined with other native medicinal plants for specific applications. While proper rongoā combinations should be learned from qualified practitioners, some simple combinations from contemporary practice include: kawakawa with mānuka leaves or honey for enhanced antimicrobial wound healing; kawakawa with koromiko for digestive support; kawakawa with harakeke (flax) for joint support. Always research individual plants thoroughly and start with low doses when combining herbs.

Regulatory Status in New Zealand: Kawakawa leaves and preparations are legal to harvest, prepare, and use in New Zealand for personal medicinal use. Commercial sale of kawakawa products is regulated by Medsafe (New Zealand Medicines and Medical Devices Safety Authority). Kawakawa is not currently listed as a restricted or controlled substance. However, health claims on commercial products must meet regulatory requirements. Wild harvesting must comply with the Department of Conservation (DOC) regulations if collecting from public conservation land, and private property harvesting requires landowner permission.

Storage of Preparations: Fresh kawakawa leaves can be stored in the refrigerator for 3-5 days. Dried leaves should be kept in airtight containers in a cool, dark place (shelf life 6-12 months). Tinctures have a shelf life of 3-5 years when stored properly in amber glass bottles away from heat and light. Infused oils should be stored in dark glass containers and used within 6-12 months; refrigeration can extend shelf life. Balms and salves remain stable for 1-2 years when stored in cool conditions; check for rancidity by smelling—if oil base smells off, discard.

Research Needs: While kawakawa has been used safely for centuries and emerging research supports its traditional applications, significant research gaps remain. Areas needing further investigation include: large-scale randomised controlled trials for specific conditions; optimal dosing for various therapeutic applications; detailed pharmacokinetic studies of active compounds; safety in special populations; potential drug interactions; long-term safety of regular use; comparison of different preparation methods; effects of harvest timing on medicinal potency; standardisation of commercial preparations; mechanisms of action for traditional uses; and effectiveness for specific modern health conditions. This research is beginning to emerge, particularly from New Zealand institutions, and represents an important opportunity to validate and understand traditional knowledge scientifically.

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