Houttuynia cordata (Latin name: Houttuynia cordata Thunb.) is an herb included in the Chinese Pharmacopoeia. The herbal source is the dried aerial parts of the plant Houttuynia cordata from the Saururaceae family. It is harvested in summer when the stems and leaves are lush and the flower spikes are abundant, after which impurities are removed, and it is sun-dried. Herb characteristics: The stem is flattened cylindrical, twisted, 20–35 cm long, 0.2–0.3 cm in diameter; the surface is brownish-yellow with several longitudinal ridges, nodes are distinct, and the lower nodes have remnant fibrous roots; the texture is brittle and easily broken. The leaves are alternate, with curled and wrinkled blades that become heart-shaped when flattened, 3–5 cm long and 3–4.5 cm wide; the apex is acuminate, and the margin is entire; the upper surface is dark yellow-green to dark brown, while the lower surface is gray-green or gray-brown; the petiole is slender, and the base is fused with the stipule into a sheath-like structure.