Xia Ku Cao

Prunella vulgaris L. (Lamiaceae), known as self-heal or heal-all, is a low-growing herbaceous perennial of meadows, lawns, woodland edges and disturbed ground throughout the temperate Northern Hemisphere. It produces creeping rhizomes that root at the nodes and erect to ascending, four-angled, finely hairy stems 10 to 40 cm tall. The leaves are opposite, ovate to oblong-lanceolate, 2 to 6 cm long, with entire to slightly toothed margins, a rounded to truncate base and short petioles; the uppermost pair sits directly beneath the inflorescence. The flowers are crowded in a dense, cylindrical to ovoid terminal spike 2 to 5 cm long, subtended by broad, often purplish, ciliate bracts. Each flower is two-lipped, 1 to 1.5 cm long, typically violet-purple, occasionally pink or white, with a hooded upper lip and a three-lobed lower lip. After flowering, the persistent dried spike, brown and rattling, is harvested in summer and constitutes Xia Ku Cao in Chinese medicine.