1.When there is blood in the stool. Blood in the stool, for example, blood-stained hand paper after a bowel movement, or blood dripping in the stool, or blood spraying in the stool. Or pus and blood stool. 2.When there is anal pain, anal itching, anal dampness, etc. The pain is persistent, that is, it hurts all the time and gradually worsens. For example, thrombosed external hemorrhoid, perianal abscess, etc. 3.When there is prolapse symptom or swelling in or around the anal opening. When a swelling comes out during defecation, it can be returned by itself after defecation, or it can be rubbed and sent by hand, or it cannot be returned. When there is a soft or hard swelling at or around the anal opening. 4.Constipation or change in bowel habits. Such as straining to defecate, incomplete defecation, and increased frequency of defecation.