The possible reasons for feeling a foreign body in the anus after a bowel movement are as follows: 1. Inflammation of the rectum: Inflammation of the rectum can be a bacterial infection, or a viral infection, and possibly autoimmune enteritis, such as ulcerative colitis and Crohn’s disease. As inflammation can lead to local exudation and irritation around the anus, resulting in urgency and feeling of a foreign body in the anus.2. Hemorrhoids: Especially more serious internal hemorrhoids, or thrombosed external hemorrhoids, or when hemorrhoids are combined with infection, they are more likely to appear.3. Tumors: Feeling of a foreign body in the anus after a bowel movement can also be caused by rectal tumors, which can be rectal adenomas or due to malignant rectal tumors. If you find that you feel a foreign body in your anus after defecating, what exactly is going on, it is recommended that you go to a regular specialist hospital for systematic examination in time so as to make a clear diagnosis.