Gypsywort

European Bugleweed, Water Horehound, Ou Di Sun. Lycopus europaeus, commonly known as gypsywort or bugleweed is a perennial herbaceous plant in the mint family (Lamiaceae).

It has a long history of medicinal use and ecological significance across Europe and parts of Asia. This species originating from Europe is one of the only plant remedies for an overactive thyroid gland. It acts as an astringent and tends to equalize circulation, thus calming the heart palpitations common to the condition.

Lycopus europaeus has been used in traditional medicine for centuries. Ancient herbalists and physicians, including those in Greek and Roman times, noted its potential for treating ailments related to the thyroid, heart, and blood circulation. The plant was believed to have astringent properties, helping to reduce excessive bleeding and sweating.

During the Middle Ages, it was widely used in European folk medicine to treat hyperthyroidism (notably Graves’ disease) due to its mild goitrogenic effects, which suppress thyroid hormone production. It was also used as a sedative and to alleviate anxiety.

It is said that some Romani people used the juice of Lycopus europaeus to stain their skin, possibly as a temporary tattoo-like application or camouflage. This led to its common name, “gypsywort.”  While not a widely used dye today, natural dyers interested in historical techniques or experimental plant dyes occasionally explore Lycopus europaeus for its deep, earthy tones. The color intensity is enhanced when used with iron salts (iron mordants), which darken the dye to a near-black shade.

Some medieval texts also link the plant to protective charms and minor magical practices. Some old beliefs suggested that rubbing the plant’s juice on the body could help a person move unseen or avoid unwanted attention—essentially a kind of “invisibility” charm. Because it was historically used medicinally to treat conditions involving overactivity, including hyperthyroidism, some folk practices linked it to spells intended to silence gossip or prevent someone from speaking ill of another.

Lycopus europaeus grows in wetland habitats, along riverbanks, and in marshes throughout Europe and western Asia. Its presence is ecologically important, as it stabilizes riverbanks and provides nectar for pollinators. The plant’s natural compounds, including tannins and flavonoids, contribute to its medicinal properties.

Today, Lycopus europaeus is still used in herbal medicine, particularly in homeopathy and phytotherapy, for managing thyroid-related conditions and mild cardiovascular issues. Scientific research has explored its potential effects on the endocrine system, confirming some of its traditional uses. Contraindicated for pregnant and nursing women, this herb should only be used under the guidance of an experienced herbalist.

Lycopus europaeus remains a plant of historical and botanical interest, bridging traditional herbalism with modern phytochemical studies.

A robust plant with unusually textured leaves and square stems, it will grow to 4 feet with small flowers blooming along the stem. Prefers a moist, sunny location. Give it plenty of room as it will spread by runners underground and create a large patch over time. Full sun perennial. Hardy down to Zone 4.