According to the inquiry of Xiaohe medical code, you need an empty stomach to apply for a health certificate. The main diseases examined by health certificate are intestinal infectious diseases, respiratory infectious diseases and infectious diseases of other organs of digestive system. Health certificates are mainly aimed at medical practitioners, catering industry service personnel, beauty industry staff and kindergarten staff. It is necessary to draw blood to test liver function and check whether there are any diseases such as acute liver disease and viral hepatitis. Eating a meal or drinking a lot of water will seriously affect the examination of liver function.