An anal fissure is a small tear or cut in the skin around the anus which can cause pain and/or bleeding. Due to the location of fissures, they become aggravated during and after bowel movements. Symptoms of an anal fissure include pain during defecation and red blood in the stool. Constipation or diarrhea can cause a tear in the anal lining resulting in a fissure. A chronic fissure may be due to poor bowel habits, tight or spastic anal sphincter muscles, scarring or an underlying medical problem.

Historically chronic fissures were treated with surgical disruption or division of the internal anal sphincter muscle. New medications include topically applied Nitroglycerin and Nifedipine, both of which may be used to decrease anal muscle spasm. Botox A, which needs to be injected, also decreases anal muscle spasm and may reduce the need to treat fissures surgically.