Anal pain from diarrhea is caused by prolonged irritation of the intestinal mucosa as well as the perianal mucosal tissue. If the patient has a poor condition of his own, such as hemorrhoids, diarrhea can also produce significant pain. As diarrhea repeatedly stimulates the intestinal mucosa as well as the perianal mucosa, the mucosa will become edematous due to long-term stimulation, and the edematous mucosa will compress each other, thus causing painful swelling in the body and painful sensation due to direct stimulation. The phenomenon of anal pain from diarrhea is normal and can be quickly relieved after diarrhea or by means of hot compresses or sitz baths, so patients can not worry too much. If the patient has hemorrhoids or anal fissures, the skin around the anus is repeatedly stimulated by diarrhea, resulting in ruptured hemorrhoids and torn skin, which can also cause more intense pain in the body. The anal pain caused by this condition is often accompanied by bloody stools during defecation, or even blood dripping directly out, with a bright red color. Pain in the anus due to diarrhea is generally normal and is caused by irritation of the perianal mucosa or edema of the mucosa due to irritation. However, the possibility of having an undesirable condition such as hemorrhoids cannot be ruled out. If the patient has anal pain that is difficult to relieve, it is still recommended to go to a regular hospital for a detailed examination.