Horehound is a bitter plant that is used for its various health benefits.
This plant is also called white horehound or common horehound.
The leaves and flowering tops are used to flavor beverages and candies. Horehound is also used medicinally in the form of teas, syrups, and lozenges. It’s said to help with coughs and respiratory health.
In this article, we will look at the benefits of horehound, its safety, and its history.
Table of Contents
What is Horehound?
Horehound is a perennial plant in the Lamiaceae (i.e. mint) family, it was originally cultivated in the Mediterranean, but it can now be found growing all around the world.
The scientific name of this plant is Marrubium vulgare. It’s commonly called white horehound.
The leaves and flowering tops of this plant have been used traditionally for digestive health, diabetes, and respiratory health. It’s still frequently used as a bitter tonic, expectorant, and diuretic.
While it has a long history of traditional medicine usage, modern research is just starting to prove out the health benefits of horehound.
Health Benefits of Horehound:
There are many purported health benefits of horehound. There is a good amount of research on Marrubium vulgare, however, most of it has been done via test-tube or animal studies.
There are minimal human clinical trials, which are the gold standard when it comes to proving safety and efficacy.
1. May Benefit Respiratory Health
Horehound is commonly used for respiratory health. It’s one of the herbal components in the popular cough drop Ricola.
Traditional herbalists have long used horehound to treat coughs and bronchitis. It’s said to relax the smooth muscles of the bronchus while promoting mucus production.
The European Medicines Agency notes horehound is appropriate for use as an expectorant (a medicine to help bring up phlegm) in patients with coughs associated with a cold.
Germany’s Commission E has also approved horehound for the treatment of bronchial problems.
While this herb is popular as a treatment for various respiratory complaints, there is minimal clinical research backing these claims.
In vitro studies (i.e. test tube studies) show that horehound has strong antioxidant and anti-inflammatory properties. These properties may be the mechanisms of action for horehound’s respiratory benefits. We will dig into this below.
Summary:Horehound has a long history of use for respiratory health, especially for helping to relax the bronchioles and remove phlegm. Various governmental health agencies have approved horehound for use in respiratory health complaints. Human clinical trials are needed to prove the efficacy and mechanism(s) of action.
2. Anti-Inflammatory Properties
A combination of lab research and animal studies shows that horehound has strong anti-inflammatory activity.
The body produces inflammation when it senses harmful stimuli. The immune system then acts by removing the harmful stimuli and initiating the healing process. Thus, inflammation is a defense mechanism that is vital to health. However, too much inflammation (i.e. chronic inflammation) is tied with a wide variety of negative health outcomes.
An animal study showed that mice given horehound had a significant reduction in inflammation (87%). Another animal study found similar anti-inflammatory properties. They also found that it has an anti-inflammatory action similar to that of aspirin.
A test-tube study looking at various compounds in horehound (including β-glucopyranoside and oleanolic acid) found that these compounds inhibited the formation of hormones, such as prostaglandins, which contribute to the production of inflammation.
Summary:A variety of animal and test-tube studies have shown that horehound has strong anti-inflammatory properties. Further human clinical trials are needed to corroborate these initial promising findings.
3. Antioxidant Properties
A combination of animal and laboratory studies has shown that horehound has antioxidant properties.
Antioxidants help to neutralize free radicals, which are known to cause cell damage in the body. Free radicals are molecules that contain an unpaired electron. Free radicals cause oxidative stress in the body, which is considered to be the primary cause of aging and a wide variety of human diseases, such as cancers, diabetes, neurodegenerative disorders, and rheumatoid arthritis.
Over ten different laboratory studies on Marrubium vulgare show that this herb has potent antioxidant capabilities. While these initial test-tube studies show promise, further clinical research is needed.
Summary:Lab-based studies show that horehound has strong antioxidant activity. While these studies are promising, human clinical trials are needed to verify this herb’s true antioxidant capacity.
4. May Help Regulate Blood Sugar
One of the traditional uses of horehound was as an anti-diabetic herb.
Various animal studies have shown that horehound has a blood sugar-regulating effect. Many of these studies looked at mice with type II diabetes. One study, in particular, found that the horehound decreases blood sugar levels, as well as total lipids, triglycerides, and cholesterol levels.
The lone human clinical trial involving horehound was conducted in 2004 on its ability to impact blood sugar levels.
In this clinical trial, horehound leaf extract was evaluated for its clinical effect in 22 individuals with type 2 diabetes. The results showed that horehound reduced glucose levels by only 0.64%, cholesterol by 4.16%, and triglycerides by 5.78%
While this study provided disappointing results, a reassessment paper written in 2017 noted that the blood sugar-regulating effects of horehound should be re-evaluated. The original 2004 study used a water-based extract, which didn’t contain 6-octadecynoic acid, the molecule that’s thought to be responsible for horehound’s anti-diabetic effects.
It appears that a new clinical trial is needed to verify once and for all whether horehound has blood sugar-regulating properties.
Summary:Animal studies show that horehound has much promise as an antihyperglycemic herb. However, a 2004 human clinical trial produced lackluster results. A recent review noted that the trial may have missed out on testing a key molecule found in horehound. A new clinical trial testing this herb and its 6-octadecynoic acid content is needed.
5. Other Benefits
Other benefits of horehound include:
- May Support Liver & Kidney Health – A study found that horehound helped to protect liver and kidney function in mice.
- May Have Anti-Proliferative Properties – A study found that the essential oil found in horehound worked to inhibit the proliferation of cancer cells.
- May Have Antimicrobial Activity – A lab study found that horehound has the ability to kill Gram-positive bacteria as well as Botrytis cinerea fungi.
- May Support Digestion: In the King’s American Dispensatory, Drs. Felter and Lloyd (1898) mention that horehound is a bitter herb that may be used as a tonic for indigestion.
While these varied health benefits are interesting, human clinical trials are needed to corroborate these findings in animal and cell culture studies.
Summary:Horehound has been tied to a wide variety of health benefits. Human clinical trials are needed to verify these findings.
White Horehound Safety:
Safety Class: 2B
Interaction Class: A
The Botanical Safety Handbook rates horehound as being in the safety class of 2B, meaning it should be avoided during pregnancy except under the supervision of a qualified healthcare practitioner.
It has an interaction class of “A” which suggests that no clinically relevant adverse reactions are expected to occur.
In general, this herb is well-tolerated and safe to take for most individuals.
Pregnancy & Lactation:
This herb is not for pregnancy except under the supervision of a qualified practitioner. It was traditionally used as an emmenagogue and was said to be able to stimulate the labor process.
There is no modern clinical research looking at the safety of horehound during lactation.
Tincture: 1-2mL three times per day of a 1:5 tincture (in 40% alcohol).
Infusion: Pour 1 cup of boiling water over 0.5-1 teaspoon of dried herb and infuse for 10-15 minutes. Drink three times per day.
Whole Herb: Germany’s Commission E recommends a daily dose of 4.5 grams of dried herb or 2-6 tablespoons of pressed juice.
Horehound grows readily around the world. Like many other plants in the Lamiaceae family, it flourishes in waste places and by roadsides.
This plant does not have any sustainability concerns.
Horehound contains monoterpenes such as camphene, p-cymol, fenchene, limonene, α-pinene, sabinene, and α-terpinolene. Non-volatile monoterpene derivatives are also present in the plant with monoterpene marrubic acid and monoterpene glycoside sacranoside A.
Sesquiterpene lactone vulgarin, β-sitosterole, lupeol, and β-amyrin types of triterpenoids such as oleanolic acid have been identified in M. vulgare extracts.
Also includes diterpene lactones, including marrubiin, pre-marrubiin, 12(S)-hydroxymarrubiin, 11-oxomarrubiin, 3-deoxo-15(S)-methoxyvelutine, marrubenol, marruliba-acetal, cyllenil A, polyodonine, and preleosibirin.
Naming & Taxonomy:
The scientific name for horehound is Marrubium vulgare.
The Romans esteemed horehound for its medicinal properties, and its Latin name “Marrubium” is said to be derived from “Maria urbs”, an ancient town in Italy.
Other authors derive its name from the Hebrew marrob (bitter), and state that it was one of the bitter herbs used by the Jewish people during the Feast of Passover.
The word “vulgare” simply means common; this references white horehound being the common form of horehound.
As a plant, white horehound is extremely hardy and easily grown. It flourishes best in dry, nutrient-depleted soil.
It can be propagated from seeds sown in spring, cuttings, or by dividing the roots (the typical method).
As a plant, horehound grows approximately one foot tall. During the early growth stages, this plant is densely covered with a thick, white, and cottony fuzz. Hence the common name “white horehound.”
History & Traditional Use:
Horehound has been traditionally used in various parts of Europe, France, Pakistan, Brazil, Tunisia, and Morocco.
In Germany, M. vulgare is traditionally used as a bitter remedy for digestive health. In Western Herbalism and throughout the Mediterranean region, it was used for various respiratory health complaints.
One researcher noted that horehound was traditionally used to treat diabetes in the country of Algeria.
In conclusion, horehound appears to be a safe and well-tolerated herb.
Common usage tells us that this herb is helpful for various respiratory complaints.
Laboratory research shows that horehound is promising a herb for helping reduce inflammation and decrease free radical damage. Researchers are still unsure about its effect on blood sugar regulation.
It’s worth looking into white horehound if you are needing support in any of these areas. As always, make sure to consult your doctor before making any changes to your diet or adding a new supplement.
Monographs. Newton, MA: Integrative Medicine Communications; 2000.
Gardner, Z. & McGuffin, M. (2013). Botanical safety handbook (2nd edition). American Herbal Products Association.
Grieve, M. (1931). White Horehound. Botanical.com. Retrieved from https://www.botanical.com/botanical/mgmh/h/horwhi33.html
Hoffman, D. (2003). Medical herbalism: The science and practice of herbal medicine. Healing Arts Press.