White Horehound

Marrubium vulgare

Common & Folk Names

• Common Horehound
• White Horehound
• Hoarhound
• Marrubium
• Houndsbane
• Llwyd y Cwn (Welsh)

Plant Family

Lamiaceae (Formerly Labiatae)

Geographic Location

Native to Europe, North Africa, and temperate regions of Asia. Found from Britain and Scandinavia south to the Mediterranean and North Africa, and east to central Asia. Now naturalised widely in temperate regions worldwide including North America, Australia, and New Zealand. Thrives in dry, disturbed areas in temperate climates.

Habitat

Naturally grows in dry, waste places, roadsides, disturbed ground, pastures, and fields. Prefers well-draining soil with full sun. Tolerates poor, dry soils and drought conditions. Found from sea level to moderate elevations. Often appears as a weed in suitable conditions.

Growing Conditions

Sun: Full sun; requires direct sunlight for best growth

Soil: Well-draining, light, sandy or gravelly soil; tolerates poor, dry soils; pH 6.5-8.0 (slightly acidic to alkaline); intolerant of waterlogged conditions

Propagation: Grow from seed sown in spring (germinates readily); divide established plants in spring or autumn; self-seeds prolifically in suitable conditions

Care: Water sparingly once established; very drought-tolerant; requires minimal fertilisation; cut back after flowering to maintain shape; generally pest and disease-free; can become weedy and spread; aromatic foliage may deter some pests

NZ Planting Calendar

Sowing (seed): Spring (September-November); sow seeds on soil surface or lightly cover; thin seedlings once established

Propagation (cuttings/division): Divide in spring (September) or autumn (March-April)

Planting: Spring (September-November) or autumn (March-May); plant in well-draining soil in sunny position

Growth: Perennial herb; semi-evergreen to deciduous depending on climate; grows 30-60cm tall; forms bushy clumps with square stems characteristic of Lamiaceae family

Flowering: Summer (December-February in NZ) with whorls of small white flowers along stems

Harvest: Aerial parts harvested just before or during flowering (December-February) when bitter principles are most concentrated; leaves can be harvested throughout growing season

Note: Naturalised as a weed in many parts of NZ; common in dry, disturbed areas particularly in North Island; grows well in drier regions (Hawke’s Bay, Marlborough, Canterbury, Central Otago); may struggle in very wet areas; considered a weed in agricultural areas but valued medicinally; self-seeds readily and can spread; distinctive grey-green woolly foliage makes identification easy; tolerates poor conditions well

Harvesting Guidelines

Harvest aerial parts (leaves, flowering tops, stems) just before or during flowering when bitter principles (marrubiin) are most concentrated. In NZ, this typically occurs in summer (December-February). Cut stems 5-10cm above ground level, leaving enough growth for plant recovery. Harvest in dry weather after morning dew has evaporated. The distinctive woolly, grey-green foliage and intensely bitter taste are characteristic. Tie stems in small bunches and hang to dry in well-ventilated, shaded area at temperatures not exceeding 35°C. Properly dried horehound retains grey-green colour and woolly texture. Store dried herb in airtight containers away from light and moisture. High-quality horehound has intensely bitter taste (indicating marrubiin content) and aromatic scent.

The abundance of horehound as a naturalised weed in many areas makes sustainable harvesting straightforward—the plant regenerates readily and harvesting can even help control spread.

Parts Used

• Aerial parts (leaves and flowering tops – primary medicinal parts)
• Leaves (can be harvested separately before flowering)

Constituents & their Actions

Horehound’s therapeutic properties arise primarily from bitter principles (particularly marrubiin), volatile oils, flavonoids, and other compounds that provide expectorant, antispasmodic, and digestive-stimulating effects.

Bitter Principles (Diterpenes):

These intensely bitter compounds are central to horehound’s therapeutic effects. The main bitter principle in horehound is:

• Marrubiin (the primary bitter lactone)
• Premarrubiin
• Related diterpene lactones

The main actions of marrubiin and related compounds are:

• Provide intensely bitter taste that stimulates digestion
• Exhibit expectorant effects through reflex stimulation
• Demonstrate mild cholagogue effects (stimulate bile production)
• May have mild vasodilatory properties
• Contribute to appetite stimulation

Volatile Oil:

Present in small amounts (0.05-0.5%), contributing to aromatic properties.

The main actions of volatile oil are:

• Contribute to expectorant effects
• Provide mild antimicrobial activity
• Support overall therapeutic profile
• Add aromatic quality

Flavonoids:

Various plant compounds with physiological effects.

The main actions of these flavonoids are:

• Provide antioxidant protection
• Support anti-inflammatory effects
• Contribute to vascular health
• Enhance therapeutic effects

Tannins:

Astringent compounds present in moderate amounts.

The main actions of tannins are:

• Provide astringent effects
• Support wound healing (topical)
• Tone mucous membranes
• Contribute to antimicrobial activity

Phenolic Acids:

Including caffeic acid and chlorogenic acid derivatives.

The main actions of these compounds are:

• Provide antioxidant effects
• Support anti-inflammatory properties
• Contribute to antimicrobial activity

Actions with Mechanisms

Expectorant:
Horehound is a traditional expectorant herb, promoting the clearance of mucus from the respiratory tract. The primary mechanism involves the bitter principles (particularly marrubiin) stimulating bitter taste receptors on the tongue, which in turn triggers a reflex that increases respiratory secretions. This reflex expectorant action thins mucus and promotes expectoration. Additionally, the volatile oils have direct effects on respiratory mucosa, stimulating secretory cells and enhancing ciliary action (movement of tiny hairs lining airways that push mucus upward). The combination of reflex and direct mechanisms provides reliable expectorant effects, making horehound valuable for productive coughs with thick mucus, chronic bronchitis, and congested respiratory conditions.

Antispasmodic (Respiratory and Digestive):
Horehound relaxes smooth muscle in both the respiratory and digestive tracts. The bitter principles and volatile oils act on smooth muscle, producing relaxation that in turn eases spasmodic coughs, reduces bronchospasm, and calms digestive cramping. The respiratory antispasmodic effects make horehound valuable for dry, irritating, spasmodic coughs and for reducing bronchial constriction. The digestive antispasmodic effects support use for cramping, bloating, and spasmodic digestive complaints. The dual antispasmodic action (respiratory and digestive) makes horehound versatile.

Digestive Bitter and Digestive Stimulant:
The intensely bitter taste of horehound (from marrubiin) provides powerful digestive stimulation. Bitter taste receptors on the tongue, when stimulated, trigger a cascade of digestive responses including increased saliva production, gastric acid secretion, bile release, and pancreatic enzyme production, which in turn enhances digestive capacity, improves nutrient absorption, and stimulates appetite in deficiency conditions. The cholagogue effects (bile stimulation) support fat digestion and liver function. Traditional use includes horehound for poor appetite, weak digestion, dyspepsia, and digestive complaints from deficiency rather than excess. The digestive effects complement the respiratory uses.

Antitussive (Cough-Suppressing):
Whilst horehound is primarily expectorant, it also has some cough-suppressing effects, particularly for irritating, non-productive coughs. The mechanisms may involve the soothing, demulcent effects of hot horehound tea and the antispasmodic effects that calm spasmodic coughs. This seemingly contradictory combination (expectorant yet antitussive) makes horehound suitable for various cough types—it promotes productive expectoration when mucus is present whilst calming irritating coughs when they’re non-productive.

Antimicrobial (Mild):
Horehound demonstrates mild antimicrobial activity against various bacteria. The volatile oils and phenolic compounds provide these effects. Whilst the antimicrobial properties are not as pronounced as some herbs, they support use for respiratory infections and may contribute to overall therapeutic effects.

Cholagogue (Bile-Stimulating):
The bitter principles stimulate bile production and release, which in turn supports fat digestion, promotes detoxification, and enhances overall digestive function. The cholagogue effects are gentle and make horehound useful for sluggish digestion (particularly of fats) and as part of liver support protocols.

Mild Diaphoretic:
When taken as hot tea, horehound promotes mild sweating, which in turn supports fever management and helps eliminate toxins through perspiration. The diaphoretic effects are gentle and traditionally used for feverish colds and flu.

Vulnerary (Wound Healing – Topical):
Traditional use includes horehound poultices or washes for wounds and skin conditions. The antimicrobial and astringent properties support healing and prevent infection. However, horehound is more commonly used internally for respiratory and digestive conditions than topically.

Main Use

Horehound is primarily used as a respiratory herb for coughs, particularly productive coughs with thick mucus, chronic bronchitis, and whooping cough. The expectorant effects thin and promote expectoration of mucus, the antispasmodic effects ease spasmodic coughs and bronchospasm, and the mild antimicrobial effects address underlying infections. This combination makes horehound valuable for various respiratory complaints.

For chronic bronchitis, horehound provides sustained support over weeks to months. The herb reduces mucus production, promotes expectoration, eases breathing, and supports overall respiratory health. Regular use can benefit individuals with chronic productive coughs.

Horehound addresses both productive, congested coughs (through expectorant effects) and dry, spasmodic, irritating coughs (through antispasmodic and soothing effects). This versatility makes horehound suitable for coughs that transition between these states or where both qualities are present.

Traditionally, horehound was highly valued for whooping cough (pertussis), where the antispasmodic effects calm the violent spasmodic coughs characteristic of this condition. Whilst modern treatment of whooping cough involves antibiotics and professional medical care, horehound may provide symptomatic support as an adjunct under supervision.

For asthma, traditional use included horehound for its antispasmodic and expectorant effects. Whilst modern treatment of asthma requires professional management, horehound may provide some support as part of comprehensive treatment under supervision.

Horehound candy, lozenges, and syrups have been traditional remedies for coughs and sore throats for centuries. The sweet preparations make the intensely bitter herb more palatable whilst retaining therapeutic effects. Horehound candy remains available commercially and represents a pleasant way to use the herb for coughs.

As a digestive bitter, horehound stimulates appetite and digestive function in individuals with poor appetite, weak digestion, and atonic dyspepsia (sluggish digestion from deficiency). The intensely bitter taste provides powerful digestive stimulation. However, the strong bitterness limits palatability for this use.

The herb’s safety, gentle action, and traditional use make it suitable for children (over 2 years), elderly individuals, and sensitive people when used appropriately. The long history of use in horehound candy and syrups demonstrates safety in paediatric populations.

Preparations

Infusion/Tea: Steep 1-2 teaspoons (2-4g) of dried herb in 250ml freshly boiled water for 10-15 minutes; strain and drink. The tea is intensely bitter. Honey can be added to improve palatability. Drink 2-3 cups daily for respiratory or digestive support.

Decoction: Some herbalists prefer decoction for horehound, simmering 1-2 teaspoons in water for 10 minutes, to extract more of the bitter principles.

Tincture (1:5, 45% alcohol): 2-4ml (40-80 drops), 2-3 times daily. The alcohol preserves the herb and provides convenient dosing.

Syrup: Traditional preparation for coughs. Simmer horehound in water, strain, add substantial honey or sugar to create thick syrup. The sweet taste masks the bitterness whilst retaining therapeutic effects. 1-2 teaspoons as needed for coughs. This is the most palatable preparation.

Horehound Candy/Lozenges: Commercial horehound candies and lozenges are available and represent traditional cough remedies. Can be made at home by creating very concentrated horehound syrup and forming into candies.

Poultice (Traditional): Crush fresh leaves or moisten dried leaves and apply to wounds or skin inflammation. Cover with clean cloth. Less commonly used than internal preparations.

Dosage

Dried Herb (infusion or decoction): 2-4g, 2-3 times daily (approximately 1-2 teaspoons per cup)

Tincture (1:5, 45% alcohol): 2-4ml (40-80 drops), 2-3 times daily

Syrup: 1-2 teaspoons (5-10ml) as needed for coughs, up to 4-6 times daily

Horehound Candy: 1-2 pieces as needed for coughs

IMPORTANT NOTES:

• Effects for chronic conditions develop over several weeks of consistent use
• For acute coughs, effects typically noticed within hours to days
• The bitter taste is intense; sweetening improves compliance
• Safe for children over 2 years in appropriate doses (typically half adult dose)

Safety & Drug Interactions

Scientific Evidence

Expectorant Effects: Traditional use is extensive across many cultures. While clinical trials specifically on horehound are limited, the mechanisms (bitter reflex stimulation of respiratory secretions and direct effects of volatile oils) are well-characterised in respiratory pharmacology. The chemical composition supports expectorant activity.

Antispasmodic Activity: Laboratory studies demonstrate smooth muscle relaxant effects of horehound extracts. The mechanisms support traditional use for spasmodic coughs and digestive cramping.

Bitter Digestive Effects: The intensely bitter taste and mechanisms (bitter taste receptor stimulation triggering digestive secretions) are well-understood. The digestive stimulating effects align with traditional use.

Antimicrobial Activity: Research demonstrates antimicrobial effects against various bacteria. Studies show activity supporting traditional use for respiratory infections.

Safety: The long history of traditional use, including in horehound candy for children, demonstrates safety. Modern safety assessments confirm good tolerability.

Chemical Composition: Extensive analysis of horehound’s constituents, particularly marrubiin and related diterpenes, confirms the presence of compounds supporting traditional uses.

Western Energetics

Temperature: Warming to neutral. Horehound’s aromatic nature and stimulating effects reflect gentle warming properties. The herb addresses cold, damp conditions whilst not being intensely heating.

Moisture: Drying. The expectorant effects move and clear damp, stuck mucus from airways. The bitter, aromatic nature contributes to drying quality. Horehound addresses excess dampness in lungs and digestive tract.

Tissue State: Particularly indicated for damp, boggy conditions with excess mucus production, poor drainage, and atrophy (deficiency). Horehound excels at moving stagnant mucus (addressing dampness) whilst the bitter principles stimulate weak digestion (addressing atrophy/deficiency). The combination makes horehound valuable for cold, damp, deficient conditions in both respiratory and digestive systems.

Taste

Intensely Bitter: The dominant taste is profound bitterness, arising from marrubiin. The bitterness is overwhelming and long-lasting, creating strong aversion in most people without sweetening. This bitterness is central to both respiratory and digestive therapeutic effects.

Aromatic/Herbal: A subtle aromatic, herbal quality accompanies the bitterness, arising from volatile oils. The aromatic notes are mild compared to the intense bitterness.

Slightly Pungent: A very subtle pungent quality may be detected beneath the bitterness.

The taste is so intensely bitter that traditional preparations almost always include substantial sweetening (honey, sugar) to make horehound palatable. Horehound candy and syrups transform the unpleasant herb into acceptable medicine.

Plant Lore

Horehound has been used medicinally for over 2,000 years, with documentation in ancient Egyptian, Greek, and Roman texts. The ancient Egyptians valued horehound for respiratory complaints, and the herb appears in early Egyptian medical papyri.

Ancient Greek and Roman physicians including Dioscorides (1st century CE) and Pliny the Elder documented horehound’s use for coughs, respiratory ailments, and as an antidote to various poisons. The Romans valued horehound highly and spread its use throughout their empire.

The name “horehound” likely derives from Old English “har” (hoary/grey, referring to the woolly grey foliage) and “hune” (hound), though the exact etymology is debated. Various folk etymologies connect the name to dogs, either because the plant was used to treat dog bites or mad dog bites (rabies), though evidence for these uses is limited.

In medieval Europe, horehound was cultivated extensively in monastery gardens and featured prominently in herbals. Medieval and Renaissance herbalists valued horehound for coughs, chest complaints, digestive weakness, and various other conditions. The herb was considered a “household remedy” available to common people.

The famous 17th century herbalist Nicholas Culpeper recommended horehound for coughs, shortness of breath, wheeziness, consumption (tuberculosis), and to expel “tough phlegm from the chest.” His recommendations align closely with modern respiratory uses.

Horehound candy has been made for centuries, representing one of the oldest forms of cough drops. The tradition of making horehound candy persists in some regions, and commercial horehound candies and lozenges remain available. The candy represents the transformation of an intensely bitter herb into a palatable and effective cough remedy.

In folk medicine across Europe and later in North America (where European settlers introduced horehound), the herb was a standard remedy for coughs and respiratory ailments. Many households kept horehound candy or syrup for treating coughs, particularly in children.

Various cultural traditions associate horehound with protection and healing. Some folk magic traditions used horehound for protection and to ward off negative influences, though the plant’s practical medicinal uses predominated.

The naturalisation of horehound as a weed in many temperate regions worldwide (including NZ, Australia, North America) demonstrates the plant’s adaptability and vigour. What was once a carefully cultivated medicinal herb became a common weed, ironically making it more accessible for medicinal use.

Additional Information

Horehound Candy Making: Traditional horehound candy can be made at home:

1. Make a very strong decoction (large amount of herb, extended simmering)
2. Strain thoroughly
3. Add sugar (typically equal weight to liquid) and simmer until hard crack stage (150°C)
4. Pour onto oiled surface and cut into pieces when cool enough to handle
5. Wrap individual pieces

The resulting candy retains horehound’s therapeutic effects whilst transforming the bitter taste into an acceptable (though still distinctive) flavour.

Horehound vs. Black Horehound: White horehound (Marrubium vulgare) should not be confused with black horehound (Ballota nigra), a different plant in the same family with different properties and uses. White horehound is the traditional respiratory herb with intensely bitter taste and woolly grey foliage. Black horehound has different properties (more nervine/sedative) and should not be substituted.

Cultivation for Medicine: Growing horehound for home medicine is straightforward:

• Very easy to grow in suitable conditions (warm, dry, well-draining)
• Drought-tolerant and low-maintenance
• Self-seeds readily (can become weedy)
• Harvest just before or during flowering for maximum bitterness
• Dries easily and stores well
• In NZ, already naturalised in many areas and can be wild-harvested

Combining with Other Respiratory Herbs: Horehound combines well with:

• Horehound + Mullein for soothing respiratory support
• Horehound + Thyme for antimicrobial respiratory effects
• Horehound + Liquorice to improve taste and add soothing effects
• Horehound + Elecampane for chronic bronchitis

Modern Usage: Whilst horehound is less commonly used in modern Western herbalism than historically (partly due to availability of other effective respiratory herbs and the challenge of the bitter taste), practitioners who use horehound value it highly for:

• Chronic productive coughs
• Spasmodic coughs
• Whooping cough (as supportive therapy)
• Combining expectorant and antispasmodic effects

Commercial Products: Horehound appears in some commercial:

• Cough syrups and lozenges
• Herbal throat sprays
• Respiratory tea blends
• Traditional candy (still available in some regions)

Sustainability: Horehound’s status as a naturalised weed in many regions (including NZ) means there are no sustainability concerns with harvesting. The plant regenerates readily from roots and seeds, and harvesting can even help control spread in areas where it’s considered weedy.

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