Foreign body sensation in the anus is a discomfort caused by non-human tissue or tissue that is out of place and irritates the sensitized rectum, anal canal and perianal area. What kind of diseases can a foreign body sensation in the anus be? (1) Anal canal inflammation Anal canal inflammation is caused by long-term fecal irritation and bad bowel habits, such as repeated constipation or repeated diarrhea can cause inflammation in the anal canal area. Because of the presence of inflammation, many patients have the phenomenon of stool holding, so prone to anal foreign body sensation. (2) Hemorrhoids Clinically, hemorrhoids are divided into external, internal, and mixed hemorrhoids based on the tooth line, and the main symptoms of external hemorrhoids are anal swelling, pain, and a foreign body sensation. The main symptoms of external hemorrhoids are anal swelling, pain, and foreign body sensation. Especially for connective tissue type external hemorrhoids, the flap is superfluous at the edge of the anus, gradually increasing in size and soft texture. (3) Rectal prolapse When the mucosal layer of the anal canal and rectum in the intestinal cavity is relaxed, it will accumulate due to the influence of gravity. When it does not prolapse out of the anus, the patient will have a distinct sensation of anal cramping. In addition, rectal prolapse can cause various kinds of inconveniences, such as difficulty in defecation, fecal incontinence and other symptoms. (4) Perianal abscess When a perianal abscess occurs subcutaneously, a lump will appear around the patient’s anus. And the lump will make the anus feel down. When the lump becomes pus, the patient will experience severe pain. (5) Rectal mucous membrane relaxation Rectal mucous membrane relaxation, also called endorectal prolapse, can be divided into stage I, II and III according to the degree of development, and its symptoms mainly include difficulty in defecation, anal cramping, and foreign body sensation in the anus. (6) Anal papillomegaly Anal papillomegaly is a benign disease, often manifested as a white papillary swelling at the anal canal, which is hard and often occurs more often. The main manifestation of anal papillitis is the sensation of a foreign body in the anus, and with the enlargement of the papillae, the papillae can come out of the anus during defecation. Smaller papillae can return to the anus by themselves after defecation, while larger ones need to be pushed back into the anus by hand. If not reset in time, it may cause anal edema, swelling and pain. There are many causes of anal foreign body sensation, and different causes correspond to different anal diseases, so patients should not blindly use drugs or prescriptions to avoid aggravating the condition and inducing more serious complications.