Dioscorea is the rhizome of Dioscorea or Dioscorea. Dioscorea is a perennial twining herbaceous vine that grows on the edges of mixed forests and under sparse forests in shady and humid places on mountainside steep slopes, valley slopes, or ditches at an altitude of 200 to 1,300 meters. It is distributed in Henan, Anhui, Zhejiang, Jiangxi, and Fujian. , Taiwan, Hubei, Hunan, Guangdong, Guangxi and other places. Mianpijie is a perennial twining herbaceous vine that grows on hillsides, roadsides, under sparse forests or in shrubs at an altitude of 450 to 700 meters. Distributed in Zhejiang, Jiangxi, Fujian, Hubei, Hunan, Guangdong, and Guangxi. Dig the rhizomes in autumn and winter, remove the fibrous roots, remove the soil, slice them and dry them in the sun.

Pijie commercial medicinal materials have two major specifications: the rhizome of Dioscorea fengyi is called "Penpijie", and the rhizome of Mianbijie is called "Mianbijie".

1. The rhizome of the rhizome is bamboo-shaped, cylindrical, branched, with a wrinkled surface, and often has stem marks or fibrous roots. The products are mostly irregular thin slices with irregular edges, about 0.5 mm thick, and some have brown-black or gray-brown skin. The cut surface is yellow-white or light gray-brown, flat and delicate, with pink and irregular yellow pulsating patterns (vascular bundles), which are extremely visible to light. The quality is loose and easy to break. The smell is slight, the taste is bitter, and slightly pungent.

2. The rhizomes of Mianpijie are mostly circular slices cut vertically or obliquely, varying in size and 2 to 5 mm thick; the outer skin is yellow-brown and thick, with many curls around the edges, and the cut surface is light yellowish white. Rough; there are scattered yellow-brown dot-like vascular bundles. The texture is loose, slightly spongy, easy to break, has a slight odor and a slightly bitter taste.

The ones with large and thin slices and yellowish-white cut surface are the best.

According to the different processing methods, the fermentation is divided into fermentation, distilled fermentation and bran fermentation. After processing, it is stored in a dry container in a ventilated and dry place.