Various anal or peripheral lesions stimulate the relevant nerves to cause anal foreign body sensation, the main causes are inflammation, anal swelling or tumor. 1. The cause of inflammation. Localized infections in the anal canal can trigger anal foreign body sensation, common diseases include sinusitis, anal papillitis, anal canal inflammation and so on. 2. The cause of anal swelling. Any localized abnormal swelling in the anus will trigger anal foreign body sensation, such as hemorrhoids, hemorrhoid nucleus enlargement will stimulate the anus to produce anal foreign body. It also includes anal papillary fibroma, perianal warts, anal fissure, anal polyp, rectal mucosal prolapse and so on. 3. Malignant tumors. For example, anal canal cancer, perianal cancer, rectal cancer, etc., may trigger anal foreign body sensation. In addition, anal neurosis may also cause anal foreign body sensation. To summarize, anal foreign body sensation, this kind of uncomfortable symptom can occur in many diseases, to clarify the condition, it is recommended to go to the hospital for further detailed examination and diagnosis.