The herb horehound has been used since Roman times as a treatment for coughs and other respiratory problems, as well as rabies. It was popular among Native North Americans as well. Teas and syrups of horehound continued to be used through the nineteenth century for coughs and lung complaints, as well as for menstrual problems. Although the herb itself has a strong bitter taste, horehound candy is considered pleasant by some, and it is still available in traditional candy stores.

Horehound is recommended by some current herbalists as a treatment for cough, asthma, and sore throat. In addition, like other bitter herbs, horehound is thought to enhance appetite, andGermany’s Commission E has approved it for this use. However, there is no reliable scientific evidence to support these uses. Only double-blind, placebo-controlled studies can prove a treatment effective, and none have been performed on horehound. (For information on why such studies are essential, seeWhy Does This Database Rely on Double-blind Studies?)

It is commonly stated that horehound loosens bronchial mucous, but there is no meaningful evidence to support this claim. Very weak evidence (far too weak to be relied upon at all), hints that horehound or its constituents marrubenol and marrubiin might have smooth-muscle relaxant,1antidiabetic,2,3blood pressure–lowering,4and nonnarcotic pain-reducing effects.5