Two treatments for fistula-in-ano were compared in a randomized trial. Times of healing were significantly shorter when the fistula was laid open (median 34 days, n = 26) than after excision (41 days, n = 21) (P less than 0.02). Revisional surgery was necessary before healing could be obtained in 3 of 26 patients after lay open operations and 2 of 21 after excision. Recurrence rates within 1 year were similar (3/24 and 2/21).