Yellow discharge from the anus may be caused by perianal abscess, anal fistula, perianal eczema and other diseases. 1. Perianal abscess: Perianal abscess is mainly caused by anal crypt infection, or it may be a purulent infection around the anorectal area caused by triggering factors such as low immunity. Patients may experience persistent pain in the perianal area, which may be aggravated by coughing, defecation, or pressure. When the abscess breaks down, there can be pus flowing from the anus, manifested as yellow discharge from the anus. 2. Anal fistula: most anal fistula is caused by perirectal anal canal abscess and other factors. Patients can see pus discharge from the anus, accompanied by itching, pain and other symptoms, manifested as yellow discharge from the anus. 3. Perianal eczema: the cause of perianal eczema is not yet clear, may be trauma, friction, often wear non-cotton underwear and other factors. Patients can appear in the perianal skin pimples, papules and other symptoms, when the blisters melt into pieces, patients scratch because of itching, will lead to yellow discharge from the anus. There are many reasons that cause yellow discharge from the anus, the cause is complex, it is recommended that patients go to the regular hospital, detailed examination and clear diagnosis, give treatment as soon as possible to avoid delaying the aggravation of the condition.