Black Horehound

Parts used and where grown

This European mint family (Lamiaceae) plant now grows in North America and on other continents as well. The leaf and flower are used medicinally. This plant should not be confused with white horehound, which acts differently.

Black horehound has been used in connection with the following conditions (refer to the individual health concern for complete information):

Science Ratings	Health Concerns
	Motion sickness Nausea
Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Science Ratings

Health Concerns

Motion sickness

Nausea

Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars

Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star

For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Historical or traditional use (may or may not be supported by scientific studies)

Black horehound has primarily been used in European traditional herbalism to relieve nausea, anxiety, or the combination of these conditions.¹ It was also used as a mild expectorant and to help normalize menstruation.

Active constituents

Phenylpropanoids—flavonoids and compounds found in the volatile oil of black horehound—are believed to be the plant’s major active constituents.² ³ A recent test tube study found black horehound phenylpropanoids to have both antioxidant properties and a sedating effect on overactive nerve cells.⁴ Although no human studies have been conducted with black horehound, the herb is believed to be useful for treating nausea associated motion sickness due to a possible effect on the central nervous system.⁵

How much is usually taken?

Black horehound is traditionally used as a tea or tincture. Approximately 2 teaspoons of the leaves are added to 1 cup hot water and allowed to steep for 10 to 15 minutes.⁶ One cup is drunk three times per day. If a tincture is preferred, 1 to 2 ml may be taken three times per day. Black horehound is rarely used alone, and is frequently combined with meadowsweet, chamomile, or ginger for relief of nausea.

Are there any side effects or interactions?

There are no reports of adverse effects from use of black horehound when taken in the amounts listed above. Black horehound was traditionally used to treat nausea during pregnancy, though no scientific evaluation of the safety or efficacy of this practice has been conducted. Some sources report that black horehound could induce miscarriage when taken in large amounts.⁷ Consult with a doctor who is trained in botanical medicine before using horehound during pregnancy.

At the time of writing, there were no well-known drug interactions with black horehound.

References

1. Hoffmann D. The New Holistic Herbal, 3rd ed. Shaftesbury, Dorset, UK: Element, 1990:181.

2. Hoffmann D. The New Holistic Herbal, 3rd ed. Shaftesbury, Dorset, UK: Element, 1990:181.

3. Daels-Rakotoarison DA, Seidel V, Gressier B, et al. Neurosedative and antioxidant activities of phenylpropanoids from Ballota nigra. Arzneim Forsch 2000;50:16–23.

4. Daels-Rakotoarison DA, Seidel V, Gressier B, et al. Neurosedative and antioxidant activities of phenylpropanoids from Ballota nigra. Arzneim Forsch 2000;50:16–23.

5. Hoffmann D. The Herbal Handbook: A User’s Guide to Medical Herbalism. Rochester, New York: Healing Arts Press, 1998, 29.

6. Hoffmann D. The New Holistic Herbal, 3rd ed. Shaftesbury, Dorset, UK: Element, 1990:181.

7. Brinker F. Herb Contraindications and Drug Interactions. Sandy, OR: Eclectic Medical Pulbications, 1998, 175.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires September 2008.