Origin: At present, yam in three places in China has applied for national geographical indication protection products. One kind is "iron stick yam", which is produced in Jiaozuo, Henan; One is "Chenjishan Medicine", which is produced in chenji, Heze City, Shandong Province, and includes "Goose Skin Rough Yam" and "Xishi Seed Yam"; One is "bergamot yam", which is produced in Wuxue, Hubei; In addition, the yam in Nanyang Township, Ruichang City, Jiangxi Province has also recently applied for national geographical indication protection products.

Yam is widely distributed in northern China, especially in Guhuaiqing Prefecture (now in Jiaozuo, Henan Province, including Boai, Qinyang, Wuzhi, wen county and other counties), which is known as "Huai Yam" and is known as "Huai Shen", ranking first in the country.

Efficacy: Yam, formerly known as Dioscorea opposita, is tonic, not stagnant, not hot or dry, and can tonify spleen and stomach yin, while tonifying lung and kidney can only be used as an auxiliary product to encourage. Chinese yam is often used in many anti-aging prescriptions. "Materia Medica Seeking Truth": "It is appropriate to use it raw in nourishing yin drugs, and it is appropriate to fry spleen and lung drugs." "This belongs to food. Although the qi is warm but flat, it is the yin of spleen and lung. Therefore, it can moisten fur and grow muscles. ..... sweet and salty, but also beneficial to kidney and yin. "