The finished product name of opposita). It is the root tuber of Dioscorea zingiberensis, a perennial herb of Dioscoreaceae, which is excavated in winter. It grows at an altitude of 350 meters to 1, 100 meters, mostly on hillsides, under valleys, among roadside shrubs, beside streams and weeds. Yam is easy to cultivate and is most suitable for growing in yellow sand soil. Chinese yam has been cultivated in China for hundreds of years. Widely distributed, including Henan, Fujian, Shandong, Hebei and other places. Rich nutrition and high medicinal value. Indications: invigorating qi and nourishing yin, invigorating spleen, lung and kidney, and stopping leucorrhea. It can be used for anorexia due to spleen deficiency, chronic diarrhea with lung deficiency, asthma and cough, nocturnal emission due to kidney deficiency, frequent micturition, deficiency heat and thirst quenching.