Early diagnosis of dysbiosis is a prerequisite for proper and effective treatment. The diagnosis of dysbiosis includes three parts: 1. the presence or absence of dysbiosis; 2. the degree of dysbiosis; 3. the cause of dysbiosis. Patients with dysbiosis often show severe diarrhea or chronic diarrhea, in the application of antibiotic therapy, if diarrhea suddenly occurs, or the existing diarrhea aggravated, that is, there may have been a dysbiosis. The degree of dysbiosis can be divided into three degrees: Ⅰ degree (mild) is reversible mild dysbiosis, can recover after removing the causative factors, the symptoms disappear, clinically seen in acute disease caused by intestinal dysfunction; Ⅱ degree (moderate) dysbiosis more serious, remove the cause often can not recover, more chronic intestinal symptoms; Ⅲ degree (severe) dysbiosis, manifested as alternating flora or dual infection. Detailed knowledge of stool characteristics and laboratory tests can identify some specific causative flora disorders, such as Shigella, Salmonella, Campylobacter, Clostridium difficile and rotavirus infections.