Huang qin is a perennial herb. Basal part of stem is prostrate on the ground and then rises to 15 to 120cm. Taproot is stout, slightly conical, and tan. Leaves are opposite, with short handle, lanceolate blade, and entire margin. Racemes are terminal. Labiate flowers are dark brown, partial to one side of the inflorescence and surrounded in sepal. Nutlets are 4, nearly round, and black. The flowering period is from July to August and the fruiting period is from August to September. Main habitats are grasslands and high dry gravelly slopes. Main chemical constituents are baicalein, baicalin, wogonin, wogonoside, neobaicalein, acetophenone, palmitic acid, oleic acid, proline, benzoic acid, radix scutellariae enzyme, and ?-sitosterol and so on.