St John’s Wort

Hypericum perforatum

Common & Folk Names

• Common St John’s Wort
• Klamath Weed
• Goatweed
• Tipton’s Weed
• Rosin Rose
• Touch and Heal
• Grace of God

Plant Family

Hypericaceae (formerly Clusiaceae)

Geographic Location

Native to Europe, western Asia, and North Africa. Now naturalised and often considered invasive in many temperate regions worldwide, including North America, South America, Australia, New Zealand, and parts of Asia. Found throughout Europe from the Mediterranean to Scandinavia. Widely distributed across temperate zones globally, thriving particularly in disturbed habitats.

Habitat

Grows in meadows, pastures, roadsides, waste ground, woodland edges, and disturbed areas. Prefers well-drained soils in full sun to partial shade. Found from sea level to mountainous regions up to 1,500 metres elevation. Thrives in poor to moderately fertile soils and tolerates drought once established. Often colonises recently cleared or disturbed land, railway embankments, and field margins.

Growing Conditions

Sun: Full sun; requires at least 6-8 hours of direct sunlight daily for optimal growth and flowering; tolerates partial shade but produces fewer flowers

Soil: Well-draining soil of average to poor fertility; tolerates sandy, loamy, or gravelly soils; pH 5.5-7.5; drought-tolerant once established; avoid waterlogged conditions

Propagation: Sow seeds in spring or autumn; divide established plants in spring or autumn; take softwood cuttings in early summer; readily self-seeds

Propagation: Seeds require light to germinate; surface sow or barely cover; stratification improves germination but is not essential; division is the most reliable method

Care: Minimal care required once established; deadhead (remove flowers) to prevent excessive self-seeding if desired; cut back after flowering to encourage fresh growth; generally pest and disease-free

NZ Planting Calendar

Sowing (seed): Spring (September-November) or autumn (March-April); surface sow as seeds need light to germinate

Propagation (cuttings/division): Divide established clumps in spring (September-October) or autumn (March-April); take softwood cuttings in early summer (November-December)

Planting: Spring (September-November) or autumn (March-May)

Growth: Hardy perennial; evergreen to semi-evergreen depending on climate; forms spreading clumps via runners

Flowering: Summer (December-February) with bright yellow, star-shaped flowers covered in tiny black dots along petal margins

Harvest: Flowering tops harvested during peak flowering (December-January) when flowers are fully open and oils are at maximum concentration

Harvesting Guidelines

Harvest the flowering tops (upper 10-15cm including flowers, buds, and leaves) during peak flowering when flowers are fully open, typically in midsummer. This timing ensures maximum concentration of hypericin, hyperforin, and other active constituents. Harvest on a dry, sunny day after morning dew has evaporated but before the heat of midday. The flowers should be bright yellow with visible oil glands (appearing as translucent dots when held up to light). Cut stems cleanly, leaving enough plant material for regrowth and seed production. For fresh preparations (particularly oil infusions), use immediately after harvesting. For dried herb, dry quickly in a warm, well-ventilated area out of direct sunlight at temperatures not exceeding 35°C to preserve the delicate constituents, especially hyperforin. Properly dried herb retains good colour. Store in airtight containers away from light and moisture. The characteristic red oil that develops during infusion indicates the presence of hypericin.

Parts Used

• Flowering tops (flowers, buds, upper leaves, and stems) – primary medicinal parts
• Occasionally flowers alone for oil preparations
• Fresh herb preferred for oil infusions; dried herb suitable for teas and tinctures

Constituents & their Actions

St John’s Wort contains a complex array of bioactive compounds that work synergistically to produce antidepressant, anti-inflammatory, antiviral, and wound-healing effects. The therapeutic properties result from naphthodianthrones, phloroglucinols, flavonoids, and various other constituents.

Naphthodianthrones (Hypericin and Pseudohypericin):

Red pigment compounds that give St John’s Wort its characteristic colour and contribute significantly to its therapeutic effects. Some of the main naphthodianthrones in St John’s Wort are:

• Hypericin
• Pseudohypericin
• Protohypericin
• Protopseudohypericin

The main actions of these naphthodianthrones are:

• Inhibit monoamine oxidase (MAO) enzymes, increasing availability of mood-regulating neurotransmitters
• Exhibit antiviral activity, particularly against enveloped viruses
• Provide photosensitising effects (responsible for both therapeutic actions and potential side effects)
• Contribute to antidepressant effects through multiple neurotransmitter interactions
• Possess anti-inflammatory and wound-healing properties

Phloroglucinols (Hyperforin and Adhyperforin):

Highly lipophilic compounds representing major active constituents with significant antidepressant activity. Some of the main phloroglucinols in St John’s Wort are:

• Hyperforin
• Adhyperforin

The main actions of these phloroglucinols are:

• Inhibit reuptake of serotonin, noradrenaline, dopamine, GABA, and glutamate (broad-spectrum neurotransmitter reuptake inhibition)
• Provide potent antibacterial effects, particularly against Gram-positive bacteria
• Exhibit anti-inflammatory properties
• Contribute significantly to antidepressant effects
• Note: Hyperforin is unstable and degrades with exposure to light and air; standardised extracts often specify hyperforin content

Flavonoids and Flavonoid Glycosides:

Plant pigments with antioxidant and various physiological effects. Some of the main flavonoids in St John’s Wort are:

• Hyperoside (quercetin-3-O-galactoside)
• Rutin (quercetin-3-O-rutinoside)
• Quercitrin
• Isoquercitrin
• Quercetin
• Kaempferol

The main actions of these flavonoids are:

• Provide antioxidant and anti-inflammatory effects
• Support vascular health and capillary integrity
• Contribute to antidepressant effects through MAO inhibition
• Exhibit anxiolytic properties
• Protect against oxidative stress

Biflavones:

Dimeric flavonoid compounds unique to Hypericum species.

The main actions of biflavones are:

• Exhibit MAO inhibition
• Provide antioxidant effects
• Contribute to the overall therapeutic profile through synergistic action

Essential Oils and Tannins:

Present in smaller amounts but contributing to the overall therapeutic effect.

The main actions of these compounds are:

• Essential oils: antimicrobial and anti-inflammatory effects
• Tannins: astringent, anti-inflammatory, and wound-healing properties
• Support the synergistic action of other constituents

Actions with Mechanisms

Antidepressant:
St John’s Wort’s antidepressant effects result from multiple mechanisms acting synergistically on various neurotransmitter systems. Hyperforin inhibits the reuptake of serotonin, noradrenaline, dopamine, GABA, and glutamate by affecting the sodium gradient that drives neurotransmitter reuptake transporters, which in turn increases the availability of these mood-regulating neurotransmitters in synaptic spaces. This broad-spectrum reuptake inhibition differs from pharmaceutical antidepressants that typically target one or two neurotransmitter systems. Hypericin and flavonoid components provide additional MAO inhibition, which prevents the breakdown of neurotransmitters, further increasing their availability. The combination of reuptake inhibition and MAO inhibition creates sustained elevation of multiple neurotransmitters, supporting mood regulation, emotional balance, and relief from depressive symptoms. Clinical studies demonstrate efficacy comparable to pharmaceutical antidepressants for mild to moderate depression.

Anxiolytic:
Multiple constituents contribute to anxiety-reducing effects through different pathways. Hyperforin’s effects on GABA reuptake increase GABAergic neurotransmission, which in turn produces calming, anxiolytic effects by enhancing the brain’s primary inhibitory neurotransmitter system. The modulation of serotonin and other neurotransmitters contributes additional anxiety relief. Flavonoids may interact with benzodiazepine receptors, providing gentle anxiolytic effects without the dependency risks of pharmaceutical benzodiazepines. The overall effect reduces symptoms of anxiety, nervous tension, and worry, particularly when these occur alongside mild to moderate depression.

Antiviral:
Hypericin and pseudohypericin exhibit significant antiviral activity through multiple mechanisms. These compounds interfere with viral replication by inhibiting viral protein synthesis and preventing viral particles from binding to host cells, which in turn reduces viral load and limits infection spread. The photosensitising properties of hypericin may contribute to antiviral effects through photoactivation, though therapeutic antiviral effects occur even without light exposure. Research demonstrates activity against various enveloped viruses including herpes simplex virus (HSV-1 and HSV-2), influenza, and potentially others. The antiviral effects are most pronounced with topical application for herpes lesions, though internal use may provide systemic benefits.

Anti-inflammatory:
Multiple constituents, including hyperforin, flavonoids, and hypericin, reduce inflammation through several pathways. Hyperforin inhibits the expression of pro-inflammatory mediators including cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX), which in turn decreases the production of inflammatory prostaglandins and leukotrienes. Flavonoids scavenge free radicals and inhibit inflammatory cytokine production, reducing oxidative stress and inflammation. The combination of COX-2 and 5-LOX inhibition provides balanced anti-inflammatory effects similar to non-steroidal anti-inflammatory drugs but with different mechanisms and fewer side effects. This action makes St John’s Wort valuable for inflammatory conditions, nerve inflammation, and inflammatory components of depression.

Vulnerary and Wound Healing:
Topical application of St John’s Wort oil promotes wound healing through multiple mechanisms. Hyperforin exhibits potent antibacterial activity against Gram-positive bacteria including Staphylococcus aureus, which in turn prevents wound infections and supports healing. The anti-inflammatory constituents reduce swelling and inflammation at wound sites, creating optimal conditions for tissue repair. Hypericin and other compounds stimulate circulation to the affected area, bringing oxygen and nutrients necessary for healing whilst removing waste products. The oil creates a protective barrier over wounds whilst allowing them to breathe, preventing infection whilst supporting tissue regeneration. Traditional use for burns, cuts, bruises, and nerve injuries is well-supported by these mechanisms.

Nervine and Nerve Restorative:
St John’s Wort provides specific support for nervous system health and repair, particularly for nerve damage and neuropathic pain. The herb’s anti-inflammatory effects reduce inflammation around injured nerves, which in turn decreases pain signals and supports nerve regeneration. Hyperforin and other constituents may promote nerve growth factor production and support myelin sheath repair, facilitating recovery from nerve injuries. The antidepressant and neurotransmitter-modulating effects support overall nervous system function and resilience. This makes St John’s Wort particularly valuable for nerve injuries, sciatica, neuralgia, and conditions involving nerve pain or damage.

Anodyne (Pain-Relieving):
Multiple mechanisms contribute to pain relief, particularly for nerve-related and inflammatory pain. The anti-inflammatory effects reduce pain-causing inflammation, whilst the nervine properties address nerve pain directly. Modulation of neurotransmitters including serotonin and noradrenaline affects pain perception pathways in the central nervous system, which in turn decreases the intensity of pain signals. Topical application provides localised pain relief for muscle aches, nerve pain, and inflammatory conditions. Internal use supports systemic pain management, particularly for chronic pain with depressive or inflammatory components.

Antibacterial:
Hyperforin demonstrates significant antibacterial activity, particularly against Gram-positive bacteria. This compound disrupts bacterial cell membranes and interferes with bacterial metabolism, which in turn inhibits bacterial growth and reduces infection. The antibacterial effects are most pronounced topically for wound infections, though internal use may provide benefits for certain infections. The selectivity for Gram-positive bacteria includes important pathogens whilst potentially sparing beneficial gut bacteria, though this requires further research.

Main Use

St John’s Wort is primarily used as a natural antidepressant for mild to moderate depression, with clinical evidence supporting efficacy comparable to pharmaceutical antidepressants but with fewer side effects. The herb excels at addressing depression characterised by low mood, loss of interest, fatigue, poor concentration, and sleep disturbances. It works particularly well for seasonal affective disorder (SAD), where the combination of antidepressant effects and traditional use for “letting in light” prove especially relevant. Unlike pharmaceutical antidepressants, St John’s Wort typically produces fewer side effects such as sexual dysfunction, weight gain, or emotional blunting, though it requires several weeks of consistent use to achieve full effects.

Beyond depression, St John’s Wort addresses anxiety, particularly when it co-occurs with mild depression. The herb helps manage nervous tension, worry, and stress-related symptoms whilst supporting overall nervous system resilience. Its nervine properties make it valuable for nerve injuries, sciatica, neuralgia, and neuropathic pain, where it reduces pain whilst supporting nerve healing and regeneration.

Topically, St John’s Wort oil (infused oil of the flowers) serves as a traditional and highly effective remedy for wounds, burns, bruises, muscle aches, and nerve injuries. The bright red oil demonstrates powerful wound-healing, antibacterial, and anti-inflammatory properties. It’s particularly valued for burns, including sunburn, where it reduces pain and promotes healing. The oil also provides relief for muscular pain, strains, sprains, and inflammatory conditions when applied topically.

The antiviral properties make St John’s Wort useful for viral infections, particularly herpes simplex virus (cold sores and genital herpes), where both internal and topical use may reduce outbreak frequency, severity, and healing time.

Preparations

Infusion (tea): Steep 1-2 teaspoons (2-4g) of dried flowering tops in 250ml freshly boiled water for 10-15 minutes; strain and drink 2-3 times daily. Note: Tea is less concentrated than standardised extracts and may be less effective for depression.

Tincture (1:5, 50-60% alcohol): Standard preparation using dried flowering tops; higher alcohol content needed to extract hyperforin and other lipophilic constituents.

Tincture (1:2, 95% alcohol, fresh herb): Fresh herb tincture using high-proof alcohol; some herbalists prefer this for maximum constituent extraction, particularly hyperforin.

Standardised Extract: Commercial products standardised to 0.3% hypericin and/or 3-5% hyperforin provide consistent dosing for depression treatment; tablets or capsules are most common.

Infused Oil (for topical use): Fresh flowers infused in olive oil or other carrier oil for 2-4 weeks in sunlight (traditional method) or using gentle heat; the oil turns deep red as hypericin is extracted. This is the traditional preparation for wound healing and pain relief. Strain and store in dark bottles.

Salve or Balm: St John’s Wort infused oil combined with beeswax to create a semi-solid preparation for easier topical application.

Dosage

Dried Herb (infusion): 2-4g, 2-3 times daily

Tincture (1:5, 50-60% alcohol): 2-4ml (40-80 drops), 2-3 times daily

Standardised Extract (0.3% hypericin): 300mg, 3 times daily (900mg total daily dose) for depression; full effects may take 4-6 weeks

Standardised Extract (3-5% hyperforin): Follow manufacturer’s instructions, typically 300-600mg daily

Topical Use (infused oil): Apply to affected area 2-4 times daily as needed for wound healing, burns, nerve pain, or muscle aches

Note: For depression treatment, consistent daily use for at least 4-6 weeks is necessary to achieve full therapeutic effects. Do not discontinue abruptly if taken regularly for extended periods.

Safety & Drug Interactions

Scientific Evidence

Depression: Extensive clinical research supports St John’s Wort’s effectiveness for mild to moderate depression. A Cochrane systematic review analysing 35 trials found St John’s Wort superior to placebo and comparable to standard antidepressants for treating mild to moderate depression, with fewer side effects. Meta-analyses consistently show response rates of 50-60% for mild to moderate depression. The evidence is strongest for mild to moderate depression; effectiveness for severe depression is not well-established. German health authorities approve St John’s Wort for depression, anxiety, and nervous unrest.

Seasonal Affective Disorder (SAD): Some clinical trials show benefits for SAD, with improvements in mood and reduced seasonal depression symptoms. The combination of antidepressant effects and bright yellow flowers traditionally associated with “bringing light” may have particular relevance for this condition.

Mechanisms of Action: Laboratory research confirms multiple mechanisms including serotonin, noradrenaline, and dopamine reuptake inhibition; MAO inhibition; and effects on other neurotransmitter systems. Hyperforin has been identified as the primary constituent responsible for neurotransmitter reuptake inhibition. Studies demonstrate that St John’s Wort affects multiple targets rather than a single pathway, which may explain its efficacy and relatively low side effect profile.

Wound Healing and Antibacterial Activity: Research supports hyperforin’s potent antibacterial activity against Gram-positive bacteria including antibiotic-resistant strains. Studies demonstrate wound-healing effects in animal models. Traditional topical use is supported by anti-inflammatory, antibacterial, and tissue-regenerating properties.

Antiviral Activity: Laboratory studies demonstrate antiviral effects against HSV-1, HSV-2, influenza virus, and other enveloped viruses. Clinical evidence for internal use is limited, but topical application for herpes lesions shows promise in preliminary studies.

Drug Interactions: Extensive research documents St John’s Wort’s enzyme-inducing effects and resulting drug interactions. Studies confirm significant reductions in blood levels of numerous medications, leading to regulatory warnings in many countries. The clinical significance of these interactions is well-established through case reports and pharmacokinetic studies.

Western Energetics

Temperature: Neutral to slightly cooling. St John’s Wort’s cooling quality relates to its anti-inflammatory effects and its traditional use for “hot” conditions including inflammation, nerve inflammation, and states of agitation. However, the herb is not strongly cooling and works well across various constitutional types.

Moisture: Slightly drying. The astringent properties and drying quality make St John’s Wort suitable for damp, stagnant conditions, though this is not its primary energetic action. The drying tendency is mild.

Tissue State: Particularly indicated for depression and atrophy, where tissues and spirits are depleted, lacking vitality and resilience. The herb brings “light” to dark states, restoring vitality and lifting mood. Also valuable for tension and constriction, particularly when nerve tension or spasm is present, as the herb relaxes whilst supporting nerve healing. The traditional association with light and the summer solstice reflects its ability to address darkness—both literal (SAD) and metaphorical (depression).

Taste

Bitter: The predominant bitter taste stimulates digestive function and reflects the presence of complex medicinal compounds. Bitterness is associated with cooling and drying properties and supports the herb’s anti-inflammatory and cleansing actions.

Astringent: A notable astringent quality contributes to St John’s Wort’s tissue-toning effects and supports wound healing. The astringency relates to the tannin content and the herb’s drying energetic.

Slightly Sweet: An underlying subtle sweetness, particularly noticeable in fresh flowers, indicates nourishing and restorative properties, supporting the herb’s nervine tonic effects.

Plant Lore

The name “St John’s Wort” derives from the plant’s traditional association with St John the Baptist, as it typically flowers around St John’s Day (24 June) near the summer solstice. The plant’s golden flowers were seen as symbolic of the sun at its height, and the red oil that develops when flowers are infused was associated with the blood of St John. Medieval Christians hung St John’s Wort over doors and windows on St John’s Eve to ward off evil spirits, lightning, and harmful influences.

The species name “perforatum” refers to the translucent dots on the leaves that appear as tiny perforations when held up to light. These are actually oil glands containing hypericin and other constituents. Medieval herbalists saw these “perforations” as signatures indicating the plant’s ability to heal puncture wounds and perforations in the body.

In European folk medicine, St John’s Wort was considered a powerful protective herb against evil, madness, and depression. The association with light, the sun, and midsummer gave the plant special significance as a bringer of light to darkness—both literal darkness of winter (SAD) and the metaphorical darkness of melancholy and depression. This traditional understanding aligns remarkably well with modern use for depression and SAD.

The plant was used in various folk magic traditions. Sleeping with St John’s Wort under one’s pillow on St John’s Eve was believed to bring visions of one’s future spouse. The herb was carried for protection, courage, and strength. Burning St John’s Wort was thought to banish negative energies and entities.

In ancient Greece, Dioscorides and other physicians documented St John’s Wort’s use for sciatica, burns, and wounds—uses that persist today. The plant’s medicinal use extends back at least 2,000 years across multiple cultures.

The plant’s tendency to colonise disturbed ground and spread vigorously led to its designation as a noxious weed in pastoral areas, particularly in North America and Australia, where it causes photosensitivity in grazing livestock. This dual nature—valuable medicine for humans but potentially harmful to livestock—reflects the plant’s powerful properties and the need for respect and appropriate use.

The bright red oil that develops when fresh flowers are infused in oil (traditionally by placing them in the sun) was seen as the plant’s “blood” or life force being transferred to the oil. This red oil was considered especially powerful for wound healing and was a prized remedy in traditional European medicine.

Different cultures have various names for St John’s Wort reflecting local traditions and uses. In German, it’s “Johanniskraut” (John’s herb), in French “millepertuis” (thousand holes, referring to the oil glands), and various other names across cultures, all recognising this plant’s special medicinal properties.

Additional Information

St John’s Wort’s status as both a valuable medicine and an invasive weed creates complexity. In many regions, including parts of New Zealand, the plant is classified as an unwanted organism due to its toxicity to livestock (causing photosensitivity) and its aggressive spreading in pastoral areas. Before cultivating St John’s Wort, check local regulations and consider the implications for surrounding land use.

The photosensitising effects that concern livestock keepers are generally not problematic for humans taking therapeutic doses, though fair-skinned individuals and those on other photosensitising medications should exercise appropriate sun protection.

When making St John’s Wort oil, the traditional solar infusion method involves placing fresh flowers in oil and leaving the jar in full sun for 2-4 weeks. As the hypericin is extracted, the oil turns a beautiful deep red. Some modern herbalists use gentle heat to infuse the oil more quickly, though traditional herbalists believe the solar method produces superior medicine. The resulting oil is one of herbal medicine’s most valued topical preparations.

St John’s Wort’s drug interactions, whilst extensive and important, should not overshadow its significant therapeutic value when used appropriately. For individuals not taking interacting medications, the herb provides safe, effective support for mild to moderate depression with fewer side effects than pharmaceutical alternatives. The key is thorough screening for drug interactions and professional guidance.

The herb combines well with other nervines and mood-supporting herbs when appropriate:

• St John’s Wort + Lemon Balm for mild depression with anxiety
• St John’s Wort + Skullcap for nerve pain and tension
• St John’s Wort + Vervain for nervous exhaustion
• Note: Combinations with other mood-altering herbs should be approached cautiously and ideally under professional guidance

Quality of commercial St John’s Wort products varies significantly. Standardised extracts ensure consistent dosing of active constituents, which is important for treating depression. Look for products standardised to both hypericin (0.3%) and hyperforin (3-5%) for optimal effectiveness. Products should specify Hypericum perforatum and avoid additives or fillers.

For topical use, making your own St John’s Wort oil from fresh flowers ensures quality and potency. The process is simple and the resulting oil is incomparably superior to most commercial preparations. Fresh plant tinctures also capture the full spectrum of constituents more effectively than some dried herb preparations.

Individual response to St John’s Wort varies. Some people experience significant mood improvement, whilst others notice minimal effects. As with pharmaceutical antidepressants, patience is required—full therapeutic effects typically emerge after 4-6 weeks of consistent use. If considering St John’s Wort for depression, professional support is important to monitor response and ensure appropriate care.

Sources

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