Horehound Side Effects

Horehound is a member of the mint family native to Europe and naturalized in North and South America. It grows in poor soil and areas where other plants struggle. According to the A 2 Z of Health, Beauty and Fitness website, horehound was historically used to flavor ale. Horehound is an expectorant and an effective treatment for coughs, laryngitis, lung problems and immune system boosting. According to Botanical.com, the plant was used to treat snakebites and poisonings. Horehound is generally safe when used in appropriate therapeutic dosages, according to the "PDR for Herbal Medicines."

Cardiac Effects

• VitaminStuff.com states that consuming large amounts of horehound has been known to cause tachycardiac arrhythmias. The website recommends that individuals with cardiac issues should avoid the herb until more is known about how it affects the heart. Health-care-Tips.org states that horehound may lower blood pressure. The herb should be used with caution by patients taking blood pressure medications or herbs for hypertension.

Abortifacient Effects

• According to Drugs.com, horehound has abortifacient properties and should not be taken by pregnant women. Historically it has been used to stimulate menstruation. Breast-feeding safety has not been determined, so it is not recommended for nursing mothers.

Hypoglycemic Effects

• A study published in C. R. Soc. Biologie de Paris demonstrated horehound had hypoglycemic effects in rabbits, according to Drugs.com. Diabetics and hypoglycemic patients should use horehound with caution.

Gastric Effects

• Horehound can increase the production of stomach acid. Patients with stomach ulcers, gastric dysfunctions and stomach acid production issues should use horehound with caution.

Toxicity

• There have been reports of poisoning in children when they consumed the seeds of the plant, according to Health-Care-Tips.org. Children should be cautioned not to consume the plant if it is planted in the garden.