Anal fissure is a painful condition that is caused by anodermal tearing after the passage of hard stool. Severe cases result in involuntary internal anal sphincter spasm and have traditionally been treated surgically with a lateral sphincterotomy. Investigators have demonstrated that nitric oxide causes relaxation of the smooth muscle of the anal canal, so topical nitroglycerin ointment preparations have recently been studied as an efficacious alternative to surgery. Despite the fact that there are a number of trials examining topical nitroglycerin for the treatment of anal fissures, there remains no consensus about concentrations, compositions and applications necessary to obtain good results. This review summarises current literature regarding topical nitroglycerin pharmacotherapy for anal fissure.