Dietotherapy, also known as food therapy, is a method to use food to affect all aspects of the body's functions, so as to obtain health or prevent diseases. It is generally believed that food is an edible substance that provides various nutrients for human growth and healthy survival. In other words, the most important function of food is nutrition. In fact, Chinese medicine has long recognized that food can not only nourish, but also cure diseases. For example, Zhang Xichun, a modern physician, once pointed out in The Enthusiasm of Western Medicine that food "can cure diseases and satisfy hunger; It can not only satisfy hunger, but also be palatable and treat symptoms. The disease is gradually recovering, that is, it is not symptomatic and there is no other disease. " It can be seen that food itself has the functions of "nourishing" and "treating diseases". Chinese medicine pays more attention to the characteristics of food in "nourishing" and "treating".

However, the process of diet therapy is generally long, and some less serious chronic diseases are often used, while other treatments are used for more urgent diseases.