Mean maximum anal resting pressure is directly related to the activity of the smooth muscles of the internal and external sphincters and has been found to be increased in the patients of anal fissure. It has been shown that blood flow at the posterior midline of anoderm is inversely related to the mean maximum anal resting pressure, and topical application of glyceryl trinitrate (GTN) ointments is a very successful treatment. This randomized study was designed to evaluate the relative value of a nitroglycerin patch applied at a distance from the fissure site in healing anal fissure compared to GTN ointment and compared to surgical treatment. Forty-two consecutive patients with chronic anal fissure of more than 4 months' duration were randomized into two equally sized groups: those in group A received 0.2% GTN ointment while those in group B received a 10-mg nitroglycerin patch for 8 weeks. Patients were also asked to rate their pain intensity on a scale of 0-10. Five patients were excluded for various reasons; results were analyzed for the remaining 37 patients (group A, n=18; group B, n=19). A control group C consisted of 12 patients who underwent surgical treatment. Fissures healed completely in 12 of 18 (66.7%) patients in group A, 12 of 19 (63.2%) in group B and 11/12 (91.7%) in group C. The healing rates in groups A and B did not differ significantly (P=0.7), nor was there a difference between these and surgical group C (P=0.13). The local application of GTN ointment and the nitroglycerin patch are both effective, economical, and alternative treatment options for most patients with anal fissures.