Yam is classified as a tonic, which can tonify, so it has a sweet taste, and it belongs to a tonic, so it can tonify the spleen. This is the * * * nature of qi tonic. In addition, yam enters the lung meridian and kidney meridian, which can replenish lung qi and kidney qi. In addition to invigorating qi, yam can also replenish yin. It is a medicinal material that can tonify both qi and yin blindly. Yam is slightly astringent. Astringency has the function of "harvesting", so yam can astringe the lung to relieve cough, astringe the intestine, solidify the kidney and astringe the essence. But the main thing is to consolidate kidney and essence. Yam has not only medicinal value, but also edible value. It can not only correct the deviation of body function. It can also supplement the nutrients needed by the body. So yam is both medicine and food. It is suitable for people with deficiency of both qi and yin who are emaciated and need supplementary nutrition. The better yam is Dioscorea opposita and Dioscorea opposita Thunb. For the edible method of yam powder: yam powder+japonica rice porridge, japonica rice can nourish stomach yin and protect spleen and stomach. A small amount of brown sugar can be added during breastfeeding. How to eat the whole yam: It is best not to stir-fry it, but to stir-fry it with a big fire, which will not only lose nutrition, but also weaken the effect of yam on nourishing yin. Therefore, it is best to use steaming.