Prunella vulgaris is a famous heat clearing herb in TCM

What is prunella vulgaris(Xia Ku Cao)? Medicinally it refers to the dried ears of Prunella vulgaris L., a species in the family Labiatae. Other common names include heal-all, self-heal, slough-heal, and the like. In China it is mainly grown in provinces of Jiangsu, Zhejiang, Anhui, and Henan. It is collected in summer when the ears present brownish red. Before it is used raw, the impurities should be removed and the ears should be dried.

This is a perennial herb. Opposite leaves are ovate or elliptical-lanceolate, 1.5 to 5cm long, 1 to 2.5cm wide, with an entire or a serrate margin. Verticillaster clusters into ears, 2 to 6cm long; kidney-shaped bracts are with cuspidate tip; calyx is bilabiate; corolla is purple, slightly concave on the top lip, and with fine cracks at the edge of the middle lobe of lower lip. Small nut is brown. Flowering time is from May to June and the fruiting time is from July to August.

Prunella vulgaris benefits
Prunella is usually harvested in the summer and the main medicinal part is the half-dry ear or the whole plant. Because it withers once June solstice comes, it is called Xia Ku Cao, which literally means "summer withered grass." Prunella is a treasure. That’s to say, its medicinal parts include stems, leaves, flowers, seeds, and ears. Actually this herb has long been documented in Chinese medicine classics, and widely used in traditional Chinese medicine.

This is a famous heat-clearing herb. Thanks to the cold medicinal properties, it is commonly used for the treatment of internal heat itself and a range of diseases caused by internal heat, for example, high blood pressure, herpes, goiter, lymphadenectasis, breast hyperplasia, and more. Traditionally it is taken in the form of decoction. But clinically it is rare to be used alone since it is less reliable in this case. So, very often prunella needs to work with other herbs to bring out its best healing powder.

Modern pharmacological actions of prunella
1) Its decoction, water extract, ethanol and water extract, and ethanol extract can significantly reduce blood pressure in experimental animals. All stem, leaf, ear, and whole plant are antihypertensive, but ears’ efficacy apparently is better;

2) Its decoction through alcohol deposition is with a clear anti-inflammatory effect in mice by intraperitoneal injection;

3) Its decoction in vitro has a certain inhibition on Shigella, Salmonella typhi, Vibrio cholerae, Escherichia coli, Proteus mirabilis, staphylococcus bacteria and M. tuberculosis var. hominis.