Tolmetin sodium's efficacy in preventing primary adhesions was evaluated in two adhesion models each in two species: (1) rabbit uterine horn, (2) rat uterine horn, (3) rabbit peritoneal side wall, and (4) rat peritoneal side wall. In each model a single instillation of tolmetin sodium solution into the peritoneal cavity at the time of surgery effectively reduced adhesion formation. This efficacy extended over a wide range of concentrations, volumes, and total dosages, and was similar in rabbits and rats. An aqueous solution of 1 mg/ml tolmetin sodium in 5-15 ml in rabbits and in 3 ml in rats was consistently efficacious in reducing postoperative adhesion formation.