In the case of diarrhea after anal intercourse, it may be necessary to consider the rectal irritation sign that occurs when the reflex nerve for defecation is stimulated during anal intercourse or when local inflammatory infection is caused by unclean anal intercourse. If the reflex nerve of bowel movement is stimulated during anal intercourse, i.e., the intestine is made to believe that there is fecal matter that should be expelled, the urge to defecate will occur. If before and after anal sex, effective cleaning is not done, or if the process of anal sex is rough causing damage to the intestinal mucosa, it may cause inflammatory diseases such as proctitis, and diarrhea may also occur. After anal sex diarrhea, the first thing to observe whether there is blood in the stool or the phenomenon of pus and blood stool. If there is no blood, you can take oral antidiarrheal drugs for treatment. If there is blood, pus and blood stool or no blood but more pain and diarrhea, you should go to the regular hospital anorectal department for medical examination in time to identify the cause and then treat the problem.