In a randomized trial we compared the treatment of perianal abscess by incision only (18 patients) with that by incision followed by fistulotomy 3 days later (20 patients). All patients were observed for 12 months. There were no differences between the two groups with regard to recurrent abscess/fistula, but the fistulotomy group had a statistically significantly higher prevalence of flatus incontinence. Further, fistulotomy was followed by significantly longer duration of hospitalization and by delayed healing. We recommend that fistulotomy is used only in patients with recurrent abscess.