Also known as yam, sweet potato, potato, grass, potato medicine, potato. Dioscorea opposita is the tuber of Dioscorea opposita, a perennial herb of Dioscoreaceae. The planter calls it domestic yam, and the wild yam; Chinese herbal medicines are called Dioscorea opposita, Dioscorea opposita and so on. Because of its rich nutrition, it has been regarded as a good tonic with good quality and low price since ancient times. It can be used as a staple food, a vegetable, and a snack such as candied haws. China is mainly produced in Bo 'ai, Qinyang, Wuzhi, wen county and other places in Henan Province, and it is also cultivated in Hebei, Shanxi, Shandong, Central South and Southwest China. After the stems and leaves wither in winter, dig, cut off the roots, wash and dry. There are two main types of yam cultivated in China: common yam and sweet potato. Ordinary yam tubers are smaller, among which "Jiaoban Potato" from Sichuan and other places, Huai Yam from Huai County, Shanxi Province, and Huai Yam from Nancheng, Jianghan are the most famous. Nutritional value 1. Spleen, stomach and digestion aid: Yam contains amylase, polyphenol oxidase and other substances, which is beneficial to the digestion and absorption function of the spleen and stomach, and is a dual-purpose product for nourishing the spleen and stomach blindly. 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; 2. Nourishing the kidney and replenishing essence: Yam contains a variety of nutrients, which has the functions of strengthening the body and nourishing the kidney and replenishing essence. Generally, symptoms such as nocturnal emission due to kidney deficiency, frequent urination, etc. can be taken; 3. Benefiting lung and relieving cough: Yam contains saponin and mucus, which has the function of lubrication and moistening, so it can benefit lung qi, nourish lung yin and treat lung deficiency, phlegm and cough for a long time; 4. Lowering blood sugar: Yam contains mucin, which has the effect of lowering blood sugar, and can be used to treat diabetes, which is a good diet for diabetics; 5. Longevity: Yam contains a lot of mucin, vitamins and trace elements, which can effectively prevent the deposition of blood lipids on the blood vessel wall, prevent heart disease, and achieve the effects of benefiting the mind and calming the nerves and prolonging life; 6. Anti-hepatic coma: In recent years, studies have found that yam has a sedative effect and can be used to resist hepatic coma. Applicable people 1. Suitable for diabetes, abdominal distension, weakness after illness, chronic nephritis and long-term diarrhea; 2. Yam has astringent effect, so people with dry stools should not eat it; In addition, those who are evil should not eat yam. Precautions: yam and kansui should not be eaten together; Nor should it be taken with alkaline drugs. Usage and dosage 1. yam should be soaked in salt water immediately after slicing to prevent oxidation and blackening. 2. When fresh yam is cut, there will be mucus, which is easy to slide and hurt your hand. You can wash it with water and a little vinegar first, which can reduce mucus. 3. Yam is delicate in texture and sweet in taste. However, the skin of yam is easy to cause skin allergy, so it is best to peel it, and don't touch your hands after peeling yam. Wash your hands several times immediately, otherwise you will scratch and itch. 4. Good yam skin is harmless, with mucus, white fault, more mucus and less water. The skin can be fried fresh, or dried in the sun to make soup or porridge. Peel and eat, so as to avoid abnormal taste such as hemp and thorns. 5. Fresh yam is mostly used for fatigue cough and diabetes, and fried cooked food is used to treat spleen and stomach and kidney deficiency. Edible efficacy Yam is sweet and flat, and enters the lung, spleen and kidney meridians; Not dry or greasy; Has the effects of invigorating spleen and lung, invigorating stomach and kidney, strengthening kidney and essence, improving hearing and eyesight, helping five internal organs, strengthening bones and muscles, calming nerves, and prolonging life; Indications are spleen and stomach weakness, listlessness, anorexia, chronic diarrhea, lung qi deficiency and dryness, phlegm and cough, kidney qi deficiency, soreness of waist and knees, weakness of lower limbs, thirst and frequent urination, nocturnal emission and premature ejaculation, leukorrhagia, skin swelling and obesity. Tips 1. Tonifying the spleen and stomach: treating spleen and stomach weakness, diarrhea, body fatigue, anorexia and sweating. 2. Benefiting lung and nourishing kidney: This product is not cold but not dry, and it tastes sweet and moist. It can be used to treat thirst, nocturnal emission and leukorrhagia due to lung and kidney deficiency.