Acylated flavonoid, andorn, blanc rubi, bonhomme, bouenriblé, bull's blood, common hoarhound, eye of the star, grand bon-homme, grand-bonhomme, haran haran, herbe aux crocs, herbe vierge, hoarhound, horehound, hound-bane, houndsbane, labdane diterpene marrubiin, Labiatae (family), Lamiaceae (family), lectins, Llwyd y cwn, maltrasté, mapiochin, mariblé marinclin, marrochemin, marroio, marroio-blanco, marromba, marrube, marrube blanc, marrube commun, marrube des champs, marrube officinal, marrube vulgaire, marrubenol, marrubii herba, marrubiin, marrubio, marrubium, Marrubium vulgare, marruboside, maruil, marvel, mastranzo, mont blanc, phenylethanoid glycosides, phenylpropanoid esters, Ricola®, seed of horus, sesquiterpene, soldier's tea, sterol, weisser andorn.
Note: White horehound should not be confused with black horehound (Ballota nigra) or water horehound (Lycopus americanus, also known as bugleweed).
Since ancient Egypt, white horehound (Marrubium vulgare L.) has been used as an expectorant (to facilitate removal of mucus from the lungs or throat). Ayurvedic, Native American, and Australian Aboriginal medicines have traditionally used white horehound to treat respiratory (lung) conditions. The U.S. Food and Drug Administration (FDA) banned horehound from cough drops in 1989 due to insufficient evidence supporting its efficacy. However, horehound is currently widely used in Europe, and it can be found in European-made herbal cough remedies sold in the United States (for example, Ricola®).
There is a lack of well-defined clinical evidence to support any therapeutic use of white horehound. The expert German panel, the Commission E, has approved white horehound for lack of appetite, dyspepsia (heartburn), and as a choleretic. There is promising early evidence favoring the use of white horehound as a hypoglycemic agent for diabetes mellitus and as a non-opioid pain reliever.
There is limited evidence on the safety or toxicity in humans. White horehound has been reported to cause hypotension (low blood pressure), hypoglycemia (low blood sugar), and arrhythmias (abnormal heart rhythms) in animal studies
Since ancient Egypt, white horehound has been used as an expectorant. Ayurvedic, Native American, and Australian Aboriginal medicines have traditionally used white horehound to treat respiratory (lung) conditions. The U.S. Food and Drug Administration (FDA) banned horehound from cough drops in 1989 due to insufficient evidence supporting its effectiveness. However, horehound is currently widely used in Europe, and it can be found in European-made herbal cough remedies sold in the United States (for example, Ricola®).
Animal studies and early human studies suggest that white horehound may lower blood sugar levels. White horehound has been used for diabetes in some countries, including Mexico. Further well-designed human trials are needed.
In Germany, white horehound is approved for the treatment of heartburn and lack of appetite, based on historical use. There is not enough information from scientific studies to evaluate the effectiveness of white horehound for these conditions.
Early study shows that white horehound may lower cholesterol and triglyceride blood levels. Further research is needed to confirm these results.
White horehound has been used traditionally to treat intestinal disorders. However, there are few well-designed studies in this area, and little information is available about the effectiveness of white horehound for this use.
White horehound has traditionally been used for pain and spasms from menstruation or intestinal conditions. There is a lack of reliable human studies on safety or effectiveness for this use.
Safety and effectiveness of doses has not been proven. Doses that have been used for cough/throat ailments include 10 to 40 drops of extract in water up to three times a day or lozenges dissolved in the mouth as needed. Ricola® drops are recommended by the manufacturer at a maximum of 2 lozenges every 1 to 2 hours as needed.
Doses recommended by the expert German panel, the Commission E, for treating heartburn or stimulating appetite include 4.5 grams daily of cut herb or 2 to 6 tablespoons of fresh plant juice. Other traditional dosing suggestions are 1 to 2 grams of dried herb or infusion three times daily.
There is not enough information to recommend the safe use of white horehound in children.
White horehound is generally considered to be safe when used as a flavoring agent in foods. However, there is limited scientific study of safety, and most available information is from animal (not human) research. Reported side effects include rash at areas of direct contact with white horehound plant juice, abnormal heart rhythms, low blood pressure, and decreased blood sugar (seen in animals with high blood sugar). White horehound may cause vomiting and diarrhea. Caution is warranted in people with heart disease or gastrointestinal disorders. Caution may also advisable in persons with diabetes or hypoglycemia and in those taking drugs, herbs, or supplements that affect blood sugar. Serum glucose levels may need to be monitored by a healthcare professional, and medication adjustments may be necessary.
Theoretically, white horehound may interfere with the body's response to the hormone aldosterone, which affects the ability of the kidneys to control the body's levels of water and electrolytes. These theoretical effects may cause high blood pressure, high blood sodium, low potassium, leg swelling, and muscle weakness. Individuals who have high or unstable blood pressure, high sodium, or low potassium or who are taking medications that reduce the amount of water in the body (diuretics, or "water pills") should use caution. White horehound may contain estrogen-like chemicals that either have stimulatory or inhibitory effects on estrogen-sensitive parts of the body. It is unclear what effects may occur in hormone-sensitive conditions such as some cancers (breast, ovarian, uterine) and endometriosis or in people using hormone replacement therapy/birth control pills.
Because white horehound is thought to be an expectorant in the treatment of cough or congestion, its use with cold medications that have expectorant ingredients may cause added effects. Theoretically, white horehound may reduce the effects of some medications given for vomiting (serotonin receptor antagonist drugs such as granisetron and ondansetron), migraine headache (ergot alkaloids such as bromocriptine, dihydroergotamine, or ergotamine), and antidepressants that possess serotonin activity (selective serotonin reuptake inhibitors (SSRIs) like Prozac®, Paxil®, or Zoloft®). White horehound may interact with the ability of the body to excrete penicillin. The reported ability of white horehound to cause diarrhea may cause an excessive response when combined with stool softeners or laxatives.
Large amounts of white horehound may increase the risk of abnormal heart rhythms and should be avoided by people treated with drugs that affect heart rhythm. Animal studies suggest that the use of white horehound with medications that lower blood pressure may cause a larger than expected drop in blood pressure. White horehound contains glycoside compounds that act on the heart and these theoretically could affect the activity of glycoside medications such as digoxin (Lanoxin®). Theoretically, white horehound may increase the action of the hormone aldosterone on the kidneys and it may interact with some diuretic medications.
Based on animal studies, white horehound may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. Patients taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional. Medication adjustments may be necessary. In theory, white horehound may also interact with medications used to treat thyroid disorders such as iodine, liothyronine (T3, Cytomel®), methimazole (Tapazole®), propylthiouracil (PTU), thyroxine (T4, Levoxyl®, Synthroid®), and Thyrolar® (T4 plus T3).
White horehound may contain estrogen-like chemicals that either have stimulatory or inhibitory effects on estrogen-sensitive parts of the body. It is unclear what effects may occur in people using hormonal therapies such as birth control pills or hormone replacement therapy. Based on early animal study, white horehound may lower cholesterol or triglyceride blood levels and therefore may have additive effects with other drugs with similar actions.
In theory, white horehound may lower blood pressure and may cause increased urine production. Caution is advised when using herbs or supplements that lower blood pressure or increase urination.
White horehound may contain glycoside chemicals that affect the heart and therefore should be used with caution by people taking other supplements that have glycoside ingredients. Notably, bufalin/Chan Suis is a Chinese herbal formula that has been reported as toxic or fatal when taken with cardiac glycosides.
Because white horehound may cause diarrhea, use caution if combining it with other laxative herbs.
Animal studies suggest that white horehound may lower blood sugar levels. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.
Because white horehound may contain estrogen-like chemicals, the effects of other agents believed to have estrogen-like properties may be altered. In theory, white horehound may interact with agents that affect the thyroid, such as bladderwrack. Based on early animal study, white horehound may lower cholesterol or triglyceride blood levels and therefore may have additive effects with other herbs and supplements with similar actions.
White horehound may interact with herbs and supplements taken to treat cough, vomiting, migraine headache, and depression; use cautiously.
This information is based on a professional level monograph edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com): Ethan Basch, MD (Memorial-Sloan-Kettering Cancer Center); Samuel Basch, MD (Mt. Sinai School of Medicine, NY); Anja Bevens, PharmD (Northeastern University); Dawn Costa, BA, BS (Natural Standard Research Collaboration); Mary McGarry, RPh (University of Rhode Island); David Sollars, MAc, HMC (New England School of Acupuncture); Mamta Vora, PharmD (Northeastern University); Paul Hammerness, MD (Harvard Medical School); Michael Smith, MR PharmS, ND (Canadian College of Naturopathic Medicine); Shaina Tanguay-Colucci, BS (Natural Standard Research Collaboration); Catherine Ulbricht, PharmD (Massachusetts General Hospital); Wendy Weissner, BA (Natural Standard Research Collaboration).
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Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.