Horehound extract comes from the leaves and stems of *Marrubium vulgare*, a bitter mint family herb. Its main active compounds include marrubiin and labdane diterpenes. Extract forms are often standardized, providing more consistent potency than whole-leaf preparations.
People traditionally use horehound to soothe coughs and throat irritation. It also serves as a bitter tonic taken before meals to support digestion. Common forms include tea, tincture, or liquid extract, with respiratory use on an as-needed basis.
Pregnant women should avoid horehound because labdane diterpenes can stimulate uterine contractions. The herb may also lower blood sugar, so anyone with diabetes or taking glucose-lowering medications should monitor their levels closely. Consult a healthcare provider before use while breastfeeding or taking any medication.