Peritendinous adhesions which develop in the flexor tendons of the digits after injury or operation are still a major problem in the surgery of the hand. The adhesions that are part of the healing process constitute an almost inevitable functional disability during the biological response of the tissue to injury. To achive better gliding function of flexor tendons, continuous efforts are being made to reduce peritendinous adhesions without adversely affecting the healing process itself. To reduce peritendinous adhesions, an aqueous solution of beta-aminopropionitrile (BAPN) was added to a solution of enriched native collagen (E.C.S.) and applied to the cut tendons of one group: untreated controls and controls treated with collagen solution alone comprised the other groups. Chickens from each group were sacrificed one, three and five weeks after operation. Tn he results were evaluated grossly and pathologically. The results of this experiment were as follows. 1. The collagen solution alone had the same lathylogenic effect as the beta-aminopropionitrile. 2. There were no systemic complications with beta-aminopropionitrile. 3. The beta-aminopropionitrile collagen solutions had the adverse effect on the tendon healings.