47 patients with functional chronic constipation associated with an achalasia of the anal sphincter were treated with the alpha blocking agent Phenoxybenzamin. Dosages were used according to the manufacturers' instructions. 29 of the children were completely cured. There was significant improvement in a further 13 children and only 5 patients showed no improvement. Treatment failures were associated with additional severe psychological disturbances for which psycho-therapeutic management was required.