Yam refers to yams of all origins, including iron stick yam, which refers to the best yam in Jiaozuo City, Henan Province, which is more effective in medicine. The yam is widely distributed, domestic Henan, Jiangsu, Zhejiang, Jiangxi, Fujian, Taiwan, Anhui, south of the Huaihe River, Hubei, Hunan and other places are planted. Iron stick yam is specifically refers to the yam produced in Jiaozuo City, Henan Province, also known as the Huai yam, the efficacy of the medicine is stronger than the general yam. Chinese yam is the dried rhizome of Dioscoreaceae plant Dioscorea, yam can solidify the sperm and stop the belt, tonifying the spleen, lungs and kidneys, benefiting qi and nourishing yin (tonifying qi and nourishing yin), often used in the treatment of spleen deficiency, spermatorrhea, lethargy and fatigue (tiredness and fatigue), loose stools (feces thinning and unshapely) and diarrhea, lungs, asthma and coughing, and so on. Iron yam, also known as wai yam, is more effective and therapeutic. As a tonic, yam is not recommended to be taken by people with solid or hot symptoms to avoid aggravating the condition. Some people will have increased bowel movements after taking it and are advised to use it under the guidance of a Chinese medicine practitioner.