Health food is not only food, but also common food. First of all, health food must be food, non-toxic and harmless, which meets the basic requirements of ordinary food, that is, it can provide one or more nutrients, be digested and absorbed by the human body, and be safe and harmless. Secondly, health food should have specific health care functions, which can be objectively verified by scientific experimental methods and meet the adjustment needs of special physiological functions of some special people; At the same time, it can not replace normal dietary intake and the need for various essential nutrients. Thirdly, health food is a special food suitable for specific people, and it is a special food to solve the special needs of some special people. Its target audience and consumption are limited, so it is not suitable for everyone. In addition, although health food can meet the special needs of some special people, it only participates in the physiological regulation of the body with a small amount of food, and promotes the transformation of the body from unstable or induced state to normal state, so it has a slow effect and cannot replace the therapeutic effect of drugs on patients when they are sick. Therefore, health food should not and cannot be eaten as medicine. It can't be used to treat diseases. Only by adjusting the physiological functions of the body through certain channels can we meet the requirements of the human body.