Vervain

The most commonly used species is European vervain (Verbena officinalis), though blue vervain (V. hastata) and V. macdougalii, among others, are probably interchangeable. V. officinalis is native to Europe, Asia, and Africa and has spread to North America. Other medicinal species are native to North America. The leaf and flower are used in herbal medicine.

Due to its bitter taste, herbalists used vervain to improve digestion. Vervain was also used to treat people with depression and spastic pains in the gastrointestinal tract, as a mild diaphoretic (to induce sweating and promote mild fevers), and for all manner of female reproductive system problems when associated with melancholy or anxiety.¹ Early 20th century Eclectic physicians (doctors who recommended herbal medicines) in the United States felt vervain might be helpful for mild digestive problems.² Vervain also has a reputation as a traditional remedy for stimulating production of breast milk.³

The active constituents of vervain have not been thoroughly demonstrated. Glycosides, such as verbenalin and aucubin, and a volatile oil may all contribute to its activity.⁴ No human studies have documented the use of this herb for any condition.

A tea of vervain leaves and flowers is prepared by adding 1–2 teaspoons (2–4 grams) to a pint (500 ml) of hot water which is left to steep, covered, for 10–15 minutes.⁵ Three cups (750 ml) per day are typically recommended by doctors. The taste of the tea is fairly disagreeable, therefore, most people prefer a tincture. Tincture, 1–2 teaspoons (5–10 ml) three times per day, is also suggested.⁶

No adverse effects of vervain have been reported. Vervain should be avoided during pregnancy.⁷ Although, traditionally, its use was during the last two weeks of pregnancy to facilitate labor. Vervain should be used during pregnancy only under the guidance of a healthcare professional experienced in herbal medicine.