The feeling of fluttering in the anus sometimes is mostly caused by paroxysmal spasm or contraction of anal sphincter, perianal abscess and pre-anal fissure and other factors. 1. paroxysmal spasm or contraction of the anal sphincter, in the case of a fluttering sensation in the anus, but not accompanied by other symptoms, it is possible that paroxysmal contraction or spasm of the sphincter muscle occurs, and it is not a pathological factor. 2. Perianal abscess, if there is a throbbing sensation in the anus and a lump with fluctuating sensation in the local location, or even with pain, fever and other symptoms, it may be caused by perianal abscess. 3. Pre-anal fissure, the typical symptom of anal fissure is pain during defecation and vibration sensation, which will be manifested as occasional throbbing sensation in the pre-anal fissure. If there is an abnormal feeling of trembling in the anus, it is recommended to consult a regular hospital in time, and listen to the doctor’s opinion after checking and differential diagnosis.