sweet potato is a panicum miliaceum belonging to the genus Ipomoea of Convolvulaceae. Its underground part has round, oval or spindle-shaped tuberous roots, and its stems are recumbent or ascending, occasionally twisted and multi-branched. Originated in South America and the big and small Antilles, it is widely cultivated in tropical and subtropical areas all over the world, and widely cultivated in most areas of China. Sweet potato is a high-yield and adaptable food crop, which is closely related to industrial and agricultural production and people's life. Apart from being the main grain, lump is also an important raw material for food processing, starch and alcohol manufacturing industries, and roots, stems and leaves are excellent feeds.

Dioscorea opposita is a plant of Dioscorea in Dioscoreaceae, which has twining herbaceous vines. Tubers are long cylindrical and grow vertically. Distributed in Korea, Japan and China, it generally grows on hillsides, under forests in valleys, in thickets or weeds beside streams and roadsides. Tuber is a commonly used Chinese medicine "Dioscorea opposita", which is rich in starch and can be eaten by vegetables. Taking medicine can make up the deficiency of spleen and stomach, and treat qi deficiency, dyspepsia, nocturnal emission, enuresis and nameless swelling and toxin.

sweet potato is mainly used as food, but it is a kind of healthy food with both medicine and food. Sweet potato contains dietary fiber, carotene, vitamins A, B, C and E, as well as more than 1 kinds of trace elements such as potassium, iron, copper, selenium and calcium. It has high nutritional value and is called the most balanced health food by nutritionists. But also can effectively prevent sugar from changing into fat, which is beneficial to weight loss and bodybuilding. Sweet potato contains a lot of dietary fiber, which can not be digested and absorbed in the intestine. It can stimulate the intestine, enhance peristalsis, relieve constipation and detoxify, especially for senile constipation.

Chinese yam is food and medicine. Chinese yam contains amylase, polyphenol oxidase and other substances, which is beneficial to the digestion and absorption function of the spleen and stomach. It is a dual-purpose product for medicine and food. Both spleen yang deficiency and stomach yin deficiency can be eaten. Clinically, it is commonly used to treat spleen and stomach weakness, anorexia, fatigue, diarrhea and other diseases; It contains a variety of nutrients, and has the functions of strengthening the body, nourishing the kidney and replenishing essence. Generally, symptoms such as nocturnal emission due to kidney deficiency, frequent urination, etc. can be taken; It contains saponin and mucilage, which has lubricating and moistening effects, so it can benefit lung qi, nourish lung yin and treat lung deficiency, phlegm and cough for a long time; Contains mucin, which has the functions of lowering blood sugar and preventing blood lipid from depositing on the blood vessel wall, can be used for preventing cardiovascular diseases and treating diabetes, and is a good food therapy for people with cardiovascular diseases and diabetes; Yam has a sedative effect and can be used to resist hepatic coma.