Anal fistula is usually treatable with metronidazole, but it needs to be properly administered under medical supervision. Anal fistula is usually caused by the abscess around the anorectum occurs ulceration, or incision drainage of the sequelae of lesions caused by metronidazole is mainly used for trichomoniasis, Guinea worm and anaerobic infections and other patients to use. Anal fistula patients with co-infection, the emergence of perianal fistula opening repeated pus, can be under the guidance of the doctor to use metronidazole for treatment. Patients in the use of metronidazole, should pay attention to pregnant women, lactating women, active central nervous system disease and blood disease patients and other patients should be prohibited from use. Anal fistula patients can use metronidazole, but need to be under the guidance of the doctor to use the drug, not self-medication. Patients should pay attention to appropriate rest during the treatment, avoid overwork.