Horehound (marrubium vulgare)

This woolly leaved perennial thrives in dry, sandy areas across Europe, Asia, North America, and Africa. The genus name Marrubium is thought to derive from marrob, the Hebrew word for “bitter juice,” and horehound may have been one of the original bitter herbs of the Jewish Passover tradition.

The herb’s common name possibly comes from the ancient Egyptians, who called it the Seed of Horus, or from the ancient Greeks, who were said to have used it to treat the bites of mad dogs. Folk legend held that horehound could break magic spells.

Horehound was said to relieve chronic hepatitis, tumors, tuberculosis, typhoid, paratyphoid, snakebite, worms, itches, jaundice, and bronchitis. But it was especially valued for its actions against coughs and lung troubles. Horehound cough syrups and drops were used as early as the 1600s; the English herbalist John Gerard (1545–1611) wrote that “a syrup made of the fresh green leaves and sugar is a most singular remedie against the cough and wheezing of the lungs.”

While horehound remains an ingredient in some over-the-counter and prescription drugs, especially cough syrups, today it is known best as an old-fashioned candy flavoring.

Horehound

Plant profile

Common Names: Horehound, White Horehound

Description: Herbaceous perennial, 2 to 3 feet tall, with branching stems and soft, hairy leaves with serrated edges; white flowers in dense whorls

Hardiness: To Zone 4

Family: Lamiaceae

Flowering: Spring to early summer

Parts Used: Leaves

Range/Habitat: Native to southern Europe, central and western Asia, and North Africa, and naturalized in North America; dry, sandy places

Culinary use

Horehound’s menthol-flavored leaves are used to make confections and throat lozenges. To make horehound candy, add sugar to an infusion of the leaves, then boil until the mixture reaches a thick consistency. Pour it into a shallow pan and cut it into squares after it cools.

Horehound seed can be added to iced tea and lemonade. In England, horehound has been used as a substitute for hops in beer, and horehound ale is still sold in Europe.

Medicinal use

Horehound’s primary medicinal constituents include tannin and marrubiin. (Marrubiin does not exist in the living plant but is formed during the extraction process.) Marrubiin has expectorant properties, which might contribute to the herb’s value as a cough soother. The herb also has a high concentration of mucilage, which eases sore throats. Traditionally, the leaves have been used to make a soothing tea for coughs, colds, and sore throats.

Sometimes horehound was infused with other herbs. One old-fashioned cold remedy that could be taken several times a day was a tea made from equal parts horehound, licorice root, marshmallow root, and hyssop. Mothers also gave children horehound syrup to settle an upset stomach.

Horehound tea is sometimes taken as a bitter to produce gastric action and aid digestion.

A small-scale human clinical trial involving this species showed that it had some positive effects on patients with type 2 diabetes, lowering plasma glucose levels slightly, with more substantial reductions in cholesterol and triglycerides. Further studies are needed to determine whether horehound could be used as a treatment for this condition.

Caution: Do not use this herb if you are pregnant or nursing. Also, be cautious if you have a history of heart or gastrointestinal trouble; reported side effects from using large amounts over a long period include arrhythmia, low blood pressure, and diarrhea. Do not confuse this plant with black or stinking horehound (Ballota nigra), which may be toxic in large quantities.

Other uses

In the past, horehound stems and leaves were used as insect repellent. The 1st-century Roman agriculturist Columella recommended horehound for “cankerworm” in trees; others have suggested that the herb repels grasshoppers and flies. In a 2004 lab experiment comparing the effect of eight different herbs on the feeding activity of Colorado potato beetles, an extract of Marrubium vulgare was found to be “strongly repellent.”

How to grow it

Horehound is a useful addition to any garden, as its flowers are a favorite of bees. Plant it in full sun and well-drained, sandy loam in early spring. Horehound tolerates dry conditions and can survive on as little as 12 inches of water a year. Harvest lightly the first year, cutting no more than the top third of the plant. The plants should begin to bloom in their second year. For the highest oil content, harvest the leaves just as the flower buds begin to form. The plant loses flavor quickly; to preserve the leaves, remove them immediately from the stems and chop them. When they have dried, place them in airtight jars and store them in a cool, dark location. have found that marrubic acid, formed from marrubiin, stimulates the flow of bile in rats. Horehound also serves as a mild laxative.

HOREHOUND COUGH SYRUP

You can make an old-time cough remedy by mixing horehound tea with honey. Boil 1 ounce of fresh or dried horehound leaves in 2 cups of water for 10 minutes. Strain off the leaves, then measure the remaining liquid. Add twice as much honey as liquid, and mix well; if necessary, warm the mixture over low heat until it is a uniform consistency. Pour the syrup into a clean bottle with a tight-fitting lid. Store the syrup in your refrigerator for up to 2 months. To soothe a cough, take 1 up to four times a day.