Skip to Content

Horehound

Scientific Name(s): Marrubium vulgare (Tourn.) L.
Common Name(s): Hoarhound, Horehound, Maromba, Marroio, White horehound

Medically reviewed by Drugs.com. Last updated on Aug 1, 2019.

Clinical Overview

Use

Clinical studies regarding therapeutic uses of horehound are limited. Research has centered on the potential for use in cardiovascular disease, diabetes, and pain and inflammation; however, no clinical evidence supports the use of horehound in these roles or in cough preparations.

Dosing

Clinical trials are lacking to provide dosing guidance. One clinical study evaluating the effect of horehound in type 2 diabetes used horehound infusions prepared with the leaves of M. vulgare and administered in 1 g envelopes, 3 times a day for 21 days.

Dosages of 4.5 g daily as the crude herb and 30 to 60 mL as pressed juice from the herb have been traditionally used.

Contraindications

Use in pregnancy is contraindicated.

Pregnancy/Lactation

Avoid use. Horehound reportedly has emmenagogue and abortifacient effects.

Interactions

None well documented.

Adverse Reactions

In a small clinical study, nausea, dry mouth, excessive salivation, dizziness, and anorexia were reported by some patients drinking a prepared infusion solution of dry leaves of the plant.

Toxicology

Marrubiin, one of the main constituents of M. vulgare, has a median lethal dose (LD50) of 370 mg/kg when administered orally to rats and an LD50 of 100 mg/kg when injected in mice; marrubiin was not cytotoxic to any of 66 cell lines tested. M. vulgare was given to rats at increasing doses of up to 1,000 mg/kg daily for 3 weeks, with no signs of toxicity. As a flavoring agent and essential oil, horehound has been granted generally recognized as safe (GRAS) status by the US Food and Drug Administration (FDA).

Scientific Family

  • Labiatae (mint)
  • Laminaceae

Botany

Horehound is native to Europe and Asia and has been naturalized to other areas, including the United States.1 It is a perennial, aromatic herb of the mint family. The plant grows to a height of approximately 1 m, and has oval leaves covered with white, woolly hairs. Horehound bears small, white flowers in dense whorls, which bloom from June to August.12, 3

History

The leaves and flower tops of the horehound plant have been traditionally used in the form of a bitter tonic as a home remedy for the common cold. Horehound is now primarily used to flavor liqueurs, candies, and cough drops.4 Although there is no evidence to support use in cough preparations,2, 3 the FDA has granted horehound GRAS status when consumed at concentrations used in such preparations.5 Traditional uses of plant extracts include treatment of intestinal parasites; as a diaphoretic, diuretic, and digestive aid, and appetite stimulant; and in cancer.3, 6 An unrelated species, the black horehound (Ballota nigra), is a fetid-scented perennial native to the Mediterranean region that is sometimes used as an adulterant of white horehound.2

Chemistry

Horehound contains 0.3% to 1% of the bitter principle marrubiin (a diterpene lactone); several diterpene alcohols (eg, marrubiol, marrubenol); and marrubiinic and marrubic acids. Phenylpropanoid esters and glycosides, as well as a phenylethanoid glycoside (marruboside) have been isolated from the aerial parts.2, 7, 8

Additional identified compounds include alkaloids, alkanes, flavonoids, tannin, pectic substances, saponin, and resin; some research has also focused on phenylpropanoid esters (including verbascoside, forsythoside, arenarioside, and ballotetroside) and glycosides.2, 9, 10, 11 Horehound also contains a small amount of essential oil, which is primarily composed of mono- and sesquiterpenes.2

Uses and Pharmacology

Antimicrobial

Animal data

In screening studies, extracts of horehound and its essential oil have demonstrated activity against Helicobacter pylori12 and several other human bacterial and fungal pathogens, including methicillin-resistant Staphylococcus aureus.13, 14, 15 Molluscicidal and mosquitocidal properties have also been demonstrated.16

Clinical data

No clinical data exist regarding the use of horehound for antimicrobial activity.

Cardiovascular effects

Animal data

Limited studies in rodents suggest that marrubiin possesses anti-inflammatory and antioxidant activity, which may be beneficial in reducing the effects of myocardial infarction.17, 18, 19 One group of researchers has demonstrated antihypertensive effects of a water extract of horehound in experiments in rodents.20, 21

Clinical data

No clinical data exist regarding the use of horehound in cardiovascular conditions. Older texts suggest that marrubiin has antiarrhythmic properties, which may induce cardiac irregularities in larger doses;3 however, animal and clinical data regarding such properties are lacking.

Diabetes

Animal data

In a study using an obese rat model, increased insulin secretion and increased low-density lipoprotein cholesterol were achieved by administration of marrubiin, which was extracted from the unrelated Leonotis leonurus plant.7, 22 In rats with induced diabetes, an aqueous extract of M. vulgare aerial plant parts decreased blood glucose and improved lipidemic indices in a dose-dependent manner.23

A study using a hydroalcoholic extract, which was dosed at 300 mg/kg via intraperitoneal injection in streptozotocin-induced diabetic rats, also noted significantly reduced fasting blood glucose (–61%), as well as reductions in total cholesterol and triglycerides of 26% and 15%, respectively.24 These activities were confirmed in another study using a methanolic extract at a dose of 500 mg/kg, in which glycemic reductions were similar to those observed in the comparator glibenclamide, and total cholesterol and triglycerides decreased while high-density lipoprotein increased.25 Some of these effects may result from 6-octadecynoic acid, obtained from the methanol leaf extract of M. vulgare, which has been identified as a potential glucose and lipid regulator that acts in a similar manner to thiazolidinediones such as pioglitazone.26

Clinical data

A small clinical study (N = 43) evaluated the effects of Cecropia obtusifolia and M. vulgare leaf extracts on blood glucose and serum lipid levels in patients with noncontrolled type 2 diabetes with poor response to conventional medical treatment.27 All patients maintained their medical treatment. In the patient group (n = 21) receiving infusions prepared with the leaves of M. vulgare and administered in 1 g envelopes 3 times a day for 21 days, the plasma glucose level was reduced by 0.64% and cholesterol and triglycerides by 4.16% and 5.78%, respectively.27

Inflammation/Analgesia

Animal data

Limited studies in rodents and in vitro experiments suggest that the chemical constituents of horehound exhibit anti-inflammatory effects. The phenylpropanoid esters acetoside, forsythoside, and arenarioside inhibited cyclooxygenase-catalyzed prostaglandin biosynthesis,10 while marrubiin reduced histamine-, carrageenan-, and formalin-induced edema.7, 28

Analgesic activity of marrubiin derivatives such as marrubiinic acid has been demonstrated by a group of researchers using animal models of pain (writhing test).29, 30, 31

Clinical data

No clinical data exist regarding the use of horehound for analgesic or anti-inflammatory effects.

Other uses

No clinical data exist regarding the use of horehound as an expectorant or for stimulation of bile production.

Antispasmodic activity has been demonstrated in isolated tissue experiments, in which calcium channel antagonism and anticholinergic effect were suggested as mechanisms of action.7, 32 Gastroprotective activity has been demonstrated in rats by a methanol horehound extract and by marrubiin.33 Antioxidant activity has also been demonstrated and may be due to the phenolic compounds in the plant leaves.11

Horehound essential oil has been shown, in in vitro studies, to have activity against several cancer cell lines;13, 14 however, marrubiin was not cytotoxic to any of the 66 cell lines tested.7

Both a methanol extract of horehound aerial parts and an extracted terpenoid were hepatoprotective, as demonstrated in rats on histological examination and in liver enzyme indices.9, 34 An aqueous extract was also found to be protective against cyclophosphamide hepatotoxicity.35

Dosing

Clinical trials are lacking to provide guidance in dosing. One clinical study evaluating the effect of horehound in type 2 diabetes used horehound infusions prepared with the leaves of M. vulgare and administered in 1 g envelopes, 3 times a day for 21 days.2, 27

Traditional dosages for digestive complaints are 4.5 g daily of the crude herb and 30 to 60 mL of a pressed juice of the herb.3, 4

Pregnancy / Lactation

Avoid use. Horehound reportedly has emmenagogue and abortifacient effects.3, 36

Interactions

Case reports are lacking; however, in vitro studies suggest that marrubiin has anticoagulant and antiplatelet activity,7, 17 while calcium channel blocking activity has been attributed to marrubenol.2 One older study suggested antiserotonin activity.2

Adverse Reactions

In a small clinical study, nausea, dry mouth, excessive salivation, dizziness, and anorexia were reported by some patients drinking an infusion of horehound.27

Older texts suggest that marrubiin has antiarrhythmic properties, which may induce cardiac irregularities in larger doses;3 however, animal and clinical data regarding such properties are lacking.

Toxicology

Marrubiin has an LD50 of 370 mg/kg when administered orally to rats and an LD50 of 100 mg/kg when injected in mice; marrubiin was not cytotoxic to any of the 66 cell lines tested.7 M. vulgare was given to rats at increasing doses of up to 1,000 mg/kg daily for 3 weeks, with no signs of toxicity.25 As a flavoring agent and essential oil, horehound has been granted GRAS status by the FDA.5

References

1. Marrubium vulgare L. [horehound]. USDA, NRCS. 2015. The PLANTS Database (http://plants.usda.gov, 2015). National Plant Data Team, Greensboro, NC 27401-4901 USA. Accessed 2015.
2. Khan IA, Abourashed EA. Leung's Encyclopedia of Common Natural Ingredients: Used in Food, Drugs, and Cosmetics. 3rd ed. Hoboken, NJ: Wiley; 2009.
3. Duke JA. Handbook of Medicinal Herbs. 2nd ed. Boca Raton, FL: CRC Press; 2002.
4. Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Integrative Medicine Communications; 2000.
5. US Food and Drug Administration (FDA). Generally Recognized As Safe(GRAS). FDA website. http://www.fda.gov/Food/IngredientsPackagingLabeling/GRAS/. Updated June 4, 2015. Accessed December 30, 2015.
6. Juárez-Vázquez Mdel C, Carranza-Álvarez C, Alonso-Castro AJ, et al. Ethnobotany of medicinal plants used in Xalpatlahuac, Guerrero, Mexico. J Ethnopharmacol. 2013;148(2):521-527.23665055
7. Popoola OK, Elbagory AM, Ameer F, Hussein AA. Marrubiin. Molecules. 2013;18(8):9049-9060.23899837
8. Sahpaz S, Hennebelle T, Bailleul F. Marruboside, a new phenylethanoid glycoside from Marrubium vulgare L. Nat Prod Lett. 2002;16(3):195-199.12049220
9. Ahmed B, Masoodi MH, Siddique AH, Khan S. A new monoterpene acid from Marrubium vulgare with potential antihepatotoxic activity. Nat Prod Res. 2010;24(18):1671-1680.20628963
10. Sahpaz S, Garbacki N, Tits M, Bailleul F. Isolation and pharmacological activity of phenylpropanoid esters from Marrubium vulgare. J Ethnopharmacol. 2002;79(3):389-392.11849848
11. Berrougui H, Isabelle M, Cherki M, Khalil A. Marrubium vulgare extract inhibits human-LDL oxidation and enhances HDL-mediated cholesterol efflux in THP-1 macrophage. Life Sci. 2006;80(2):105-112.17045616
12. Robles-Zepeda RE, Velázquez-Contreras CA, Garibay-Escobar A, Gálvez-Ruiz JC, Ruiz-Bustos E. Antimicrobial activity of Northwestern Mexican plants against Helicobacter pylori. J Med Food. 2011;14(10):1280-1283.21663492
13. Yildirim AB, Karakas FP, Turker AU. In vitro antibacterial and antitumor activities of some medicinal plant extracts, growing in Turkey. Asian Pac J Trop Med. 2013;6(8):616-624.23790332
14. Zarai Z, Kadri A, Ben Chobba I, et al. The in-vitro evaluation of antibacterial, antifungal and cytotoxic properties of Marrubium vulgare L. essential oil grown in Tunisia. Lipids Health Dis. 2011;10:161.21936887
15. Temmouri HB, Meddah AT, Sahraoui T, Meddah B. Alternative treatment of methicillin-resistant Staphylococcus aureus and extended spectrum beta-lactamases producing multiresistant gram-negative bacteria from nosocomial infection by Marrubium vulgare methanolic compounds. J Chem Pharm Res. 2014;6(6):60-64.
16. Salama MM, Taher EE, El-Bahy MM. Molluscicidal and Mosquitocidal activities of the essential oils of Thymus capitatus Hoff. et Link. and Marrubium vulgare L. Rev Inst Med Trop Sao Paulo. 2012;54(5):281-286.22983292
17. Mnonopi N, Levendal RA, Davies-Coleman MT, Frost CL. The cardioprotective effects of marrubiin, a diterpenoid found in Leonotis leonurus extracts. J Ethnopharmacol. 2011;138(1):67-75.21893184
18. Yousefi K, Soraya H, Fathiazad F, et al. Cardioprotective effect of methanolic extract of Marrubium vulgare L. on isoproterenol-induced acute myocardial infarction in rats. Indian J Exp Biol. 2013;51(8):653-660.24228389
19. Yousefi K, Fathiazad F, Soraya H, Rameshrad M, Maleki-Dizaji N, Garjani A. Marrubium vulgare L. methanolic extract inhibits inflammatory response and prevents cardiomyocyte fibrosis in isoproterenol-induced acute myocardial infarction in rats. Bioimpacts. 2014;4(1):21-27.24790895
20. El Bardai S, Lyoussi B, Wibo M, Morel N. Pharmacological evidence of hypotensive activity of Marrubium vulgare and Foeniculum vulgare in spontaneously hypertensive rat. Clin Exp Hypertens. 2001;23(4):329-343.11349824
21. El Bardai S, Lyoussi B, Wibo M, Morel N. Comparative study of the antihypertensive activity of Marrubium vulgare and of the dihydropyridine calcium antagonist amlodipine in spontaneously hypertensive rat. Clin Exp Hypertens. 2004;26(6):465-474.15554450
22. Mnonopi N, Levendal RA, Mzilikazi N, Frost CL. Marrubiin, a constituent of Leonotis leonurus, alleviates diabetic symptoms. Phytomedicine. 2012;19(6):488-493.22326550
23. Boudjelal A, Henchiri C, Siracusa L, Sari M, Ruberto G. Compositional analysis and in vivo anti-diabetic activity of wild Algerian Marrubium vulgare L. infusion. Fitoterapia. 2012;83(2):286-292.22100836
24. Azzi R, Lahfa F, Djaziri R. Phytochemical, antihyperglycemic and antihyperlipidemic study of crude hydroalcoholic extract of aerial parts of Marrubium vulgare L. in normal and streptozotocin induced-diabetic Wistar rats. Int J Pharm Sci Res. 2014;5(5):2006-2013.
25. Elberry AA, Harraz FM, Ghareib SA, Gabr SA, Nagy AA, Abdel-Sattar E. Methanolic extract of Marrubium vulgare ameliorates hyperglycemia and dyslipidemia in streptozotocin-induced diabetic rats. Int J Diabetes Mellit. 2015;3(1):37-44.
26. Ohtera A, Miyamae Y, Nakai N, et al. Identification of 6-octadecynoic acid from a methanol extract of Marrubium vulgare L. as a peroxisome proliferator-activated receptor gamma agonist. Biochem Biophys Res Commun. 2013;440(2):204-209.24025677
27. Herrera-Arellano A, Aguilar-Santamaría L, Garcia-Hernández B, Nicasio-Torres P, Tortoriello J. Clinical trial of Cecropia obtusifolia and Marrubium vulgare leaf extracts on blood glucose and serum lipids in type 2 diabetics. Phytomedicine. 2004;11(7-8):561-566.15636168
28. Stulzer HK, Tagliari MP, Zampirolo JA, Cechinel-Filho V, Schlemper V. Antioedematogenic effect of marrubiin obtained from Marrubium vulgare. J Ethnopharmacol. 2006;108(3):379-384.16846706
29. Meyre-Silva C, Yunes RA, Schlemper V, Campos-Buzzi F, Cechinel-Filho V. Analgesic potential of marrubiin derivatives, a bioactive diterpene present in Marrubium vulgare (Lamiaceae). Farmaco. 2005;60(4):321-326.15848207
30. de Souza MM, de Jesus RA, Cechinel-Filho V, Schlemper V. Analgesic profile of hydroalcoholic extract obtained from Marrubium vulgare. Phytomedicine. 1998;5(2):103-107.23195761
31. De Jesus RA, Cechinel-Filho V, Oliveira AE, Schlemper V. Analysis of the antinociceptive properties of marrubiin isolated from Marrubium vulgare. Phytomedicine. 2000;7(2):111-115.10839213
32. Schlemper V, Ribas A, Nicolau M, Cechinel Filho V. Antispasmodic effects of hydroalcoholic extract of Marrubium vulgare on isolated tissues. Phytomedicine. 1996;3(2):211-216.23194972
33. Paula de Oliveira A, Santin JR, Lemos M, et al. Gastroprotective activity of methanol extract and marrubiin obtained from leaves of Marrubium vulgare L. (Lamiaceae). J Pharm Pharmacol. 2011;63(9):1230-1237.21827496
34. Elberry AA, Harraz FM, Ghareib SA, et al. Antihepatotoxic effect of Marrubium vulgare and Withania somnifera extracts on carbon tetrachloride-induced hepatotoxicity in rats. J Basic Clin Pharm. 2010;1(4):247-254.24825994
35. Ettaya A, Dhibi S, Samout N, Elfeki A, Hfaiedh N. Hepatatoprotective activity of white horehound (Marrubium vulgare) extract against cyclophosphamide toxicity in male rats. Can J Physiol Pharmacol. 2016;94:441-447.26886858
36. Ernst E. Herbal medicinal products during pregnancy: are they safe? BJOG. 2002;109(3):227-235.11950176

Disclaimer

This information relates to an herbal, vitamin, mineral or other dietary supplement. This product has not been reviewed by the FDA to determine whether it is safe or effective and is not subject to the quality standards and safety information collection standards that are applicable to most prescription drugs. This information should not be used to decide whether or not to take this product. This information does not endorse this product as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this product. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this product. This information is not specific medical advice and does not replace information you receive from your health care provider. You should talk with your health care provider for complete information about the risks and benefits of using this product.

This product may adversely interact with certain health and medical conditions, other prescription and over-the-counter drugs, foods, or other dietary supplements. This product may be unsafe when used before surgery or other medical procedures. It is important to fully inform your doctor about the herbal, vitamins, mineral or any other supplements you are taking before any kind of surgery or medical procedure. With the exception of certain products that are generally recognized as safe in normal quantities, including use of folic acid and prenatal vitamins during pregnancy, this product has not been sufficiently studied to determine whether it is safe to use during pregnancy or nursing or by persons younger than 2 years of age.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

More about horehound

Related treatment guides

Hide