White horehound has a long history in Western herbal medicine as a remedy for ailments of the respiratory system.  Owing to its bitter nature and choleretic properties white horehound is also a valuable herb for digestive health. 

Respiratory system

With an extensive history as a cough remedy, white horehound is still recognised as an effective cough medicine today. It is particularly beneficial for dry unproductive coughs, bronchitis and catarrh. Whilst the bitter components stimulate the production of mucus white horehound’s expectorant properties facilitate the expulsion of mucus (2). When used during the severe coughing phase of whooping cough, white horehound loosens persistent and stubborn phlegm. White horehound can be used in cases of bronchitis (3).

Digestive system

The active ingredients in white horehound function as a choleretic (4), stimulating the production and flow of bile to facilitate digestion (2), consequently proving beneficial in cases of temporary appetite loss. Furthermore, its bitter properties assist in alleviating symptoms of dyspepsia, including bloating, fullness, and flatulence (1).

Hot and dry in the second degree

Adhering to the traditional Galenic approach whereby herbs are divided into qualities — hot, cold, damp, dry, then further divided into degrees — 1st 2nd 3rd and 4th, Herbalist Matthew Wood classifies white horehound as being hot and dry in the second degree. According to Wood, plants categorised as hot, exhibit warming properties and function as diaphoretics, however those hot in the second degree also possess the ability to cut through phlegm and mucus (5).

A herb of Mercury

In his writings, Nicholas Culpeper, a herbalist and astrologer of the 17th century, stated that herbs and diseases are governed by planets.  

In his posthumously published work ‘Semeotica Uranica’ (1655), Culpeper associated diseases governed by mercury as being  (6, p79) ‘all diseases of the lungs, as asthma, all imperfections of the tongue, hoarseness, coughs, snuffling in the head’.

In ‘The English Physician’ Culpeper detailed the ‘Government and Virtues’ of each herb, to assist readers in identifying the herbs necessary for addressing specific conditions and ailments (7). 

Culpeper attributed ‘hoarhound’ to Mercury, the planet closest to the sun, claiming (8, p139) ‘A decoction of the dried herb with the seed or the juice of the green herb taken with honey is a certain remedy for those that are short winded or have a cough or rheum upon the lungs. It helps to expectorate tough phlegm from the chest’. 

White horehound boasts a rich historical background as a remedy for coughs and respiratory complaints, often administered as an infusion or decoction sweetened with honey or sugar.

In the Old English Herbarium — one of the four remaining works in vernacular writing from the Anglo-Saxon period — the juice is recommended for stomach ache, additionally ‘harehune’ is noted for coughs and lung complaints. 

‘For a cold in the head and for heavy coughing, take the plant the Greeks call prassion, the Romans marubium and the English horehound, and simmer it in water. Give it to drink whenever the coughing is heavy, and it will help wonderfully’. 

‘For lung disease, take the same plant and simmer it in honey. Give it to eat, the person will be cured in a wonderful manner’ (9, pp 170–171).

During the 13th century, the Myddfai physicians began to record their usage of medicinal plants (10). They wrote of an infusion of white horehound to be consumed warm and sweetened with honey for treating pneumonia (11).

In the 17th century, Culpeper notes the widespread availability of horehound syrup in most apothecaries. He recommends it ‘to evacuate tough phlegm and cold rheum from the lungs of an aged person especially if they are asthmatic and short winded’ (6, p140).

Maude Grieve, in the 1900s, also mentions an infusion of horehound in her writings. She recommends ‘For ordinary cold, a simple infusion of Horehound is generally sufficient in itself. A wineglassful may be taken three or four times a day’ (12).

Renowned medical herbalist David Hoffmann emphasises the valuable properties of horehound in the treatment of bronchitis, particularly when dealing with a non-productive cough. He states horehound induces a relaxing effect on the smooth muscles of the bronchus, facilitating mucus production and thus promoting expectoration. Additionally, Hoffmann attributes the stimulation of bile flow and secretion from the gall bladder to the plant’s bitter action, thereby aiding the process of digestion (2).

Kerry Bone and Simon Mills note that white horehound is traditionally used as a respiratory spasmolytic. Herbs with such an action relax the bronchioles of the lungs and are therefore indicated for tight, breathless non-productive coughing and asthmatic symptoms such as wheezing (3).

Herbalists frequently combine herbs to enhance their effects, with many exhibiting synergistic properties when used together. Matthew Wood describes synergists as herbs who combined have more power than either one independently. He refers to white horehound having a synergistic effect with Elecampane (Inula helenium) (5).

Several research studies have demonstrated anti-inflammatory, antioxidant, antihypertensive, antispasmodic, analgesic, anti-hyperglycaemic and anti-hyperlipidemic properties (13,14,15) of Marrubium vulgare. 

White horehound used in Western herbal medicine for the treatment of dyspepsia is recognised for its secretory action (1,2). A 2011, in vivo study was conducted in order to assess the gastroprotective properties of white horehound extracts (Marrubium vulgare).  The study’s authors state that peptic ulcers and dyspepsia affect thousands of people around the world and therefore considered a global health problem. Due to the side effects of current medication for dyspepsia and ulcers, such as proton pump inhibitors and anticholinergics, there is a need for new effective treatments without damaging side effects (13).

Methanol extracts and diterpene lactone marrubiin were obtained from the leaves of Marrubium vulgare in order to assess the antiulcer potential (13). The study concluded that Marrubium vulgare extract and marrubiin demonstrated antiulcer activity. The research also demonstrated that the Marrubium vulgare extract and marrubiin’s gastroprotective actions were due to the ability to stimulate mucus — a protective factor, and decrease acid secretion — an aggravator (13).

Some historians believe the Latin name Marrubium originated from the Hebrew marrob ‘a bitter juice’ (16,12).

Another theory is that the plant’s common name, horehound is derived from the Anglo-Saxon word ‘hare’ meaning white or hoary, referring to the plants thick woolly hairs covering the leaves and stem (16).

Comuella, a notable author on agricultural practices during the Roman empire wrote that the juice of white horehound eliminates canker worms in trees (16,12).

Native to UK, Eurasia and North Africa (24,20) 

It is believed to be native to exposed grasslands on cliff tops and slopes that overlay limestone and chalk and sandy banks near the sea (25) in east, south, south west England and coastal areas of south Wales (23). It is naturalised in rough ground and waste places elsewhere (25). 

It thrives in poor, well-drained soil, preferring full sun (21).

Its native distribution appears to be stable; however, localised declines have occurred due to lack of grazing. Its decline in areas of naturalisation evident since the 1960s, continues, particularly inland on arable land (25).

The Vascular Plant, Red Data List, For Great Britain white horehound is categorised as least Concern (LC) (26).

A taxon is Least Concern when it has been evaluated against the criteria and does not qualify for Critically Endangered, Endangered, Vulnerable or Near Threatened. Widespread and abundant taxa are included in this category (26).

According to Mills and Bone, white horehound has been adulterated with other Marrubium spp. such as M. incanum, M. peregrinum. Black horehound (Ballota nigra) and Ballota hirsuta have also been adulterants (18).

White horehound can be grown from seed and softwood cuttings in spring (21).

White Horehound Syrup 

Ingredients 

• 18g dried horehound (Marrubium vulgare)
• 10g dried elecampane (root)(Inula helenium)
• 2g dried thyme (Thymus vulgaris)
• 1 litre cold water
• Raw cane sugar or honey (approximately 100g sugar or 150ml honey)

Method

1. Add the dried herbs and water into a pan. Cover and bring to the boil.
2. Simmer for 30 minutes.
3. Strain the contents through a muslin cloth/bag or similar material.
4. When cool enough squeeze the muslin to express as much liquid as possible.
5. Discard the herbs — compost if possible.
6. Measure the amount of liquid (decoction) retained.

For each 100ml decoction, you will need 50g of sugar or 75ml of honey to make the syrup.

If using sugar:

• Add the decoction and the required amount of sugar into to a clean pan and slowly bring to the boil, stirring continuously.
• Continuing to stir, gently simmer for approximately 1 minute, or until the liquid starts to thicken slightly.
• Remove from heat.

If using honey:

• Add the decoction into a clean pan and bring to the boil, remove the pan from the heat before adding the honey, stir until the honey dissolves.
• Allow to cool and pour into sterilised bottles, label.

Sugar is a preservative, the higher the ratio of sugar to liquid the longer the mixture will store. Using the ratio of 50g of sugar to each 100ml of liquid, or 75ml of honey to 100ml liquid, the syrup should store for 3–4 months kept in a fridge.

Dosage 

2–5 ml

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   15. Elberry A, Harraz F. M, Ghareib S. A, et al. Methanolic Extract of Marrubium vulgare Ameliorates Hyperglycemia and Dyslipodemia in Streptozotocin-induced Diabetic Rats. International Journal of Diabetes Mellitus. 2004: 26 (6): 465-474, DOI: 10.1081/CEH-200031818 
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