0.2% glyceryl trinitrate (GTN) ointment is an unlicensed treatment for chronic anal fissures. The Committee agreed that GTN has a clinically important effect on healing and is a simple and cheap treatment. It often avoids the need for surgery, as well as the delay in waiting for surgical treatment. Evidence for the use of this treatment comes from 2 RCTs which are of good quality but have fairly small sample sizes. The Committee noted that a large UK trial is due to report later this year and asked to keep a watching brief in this area. The Committee noted that GTN is contraindicated for patients with certain conditions and for those taking sildenafil. Given concern about misdiagnosing potentially curable anorectal cancers, the Committee also stated that patients with chronic anal fissures should be positively diagnosed by full examination before receiving GTN treatment.