In a double blind, controlled clinical study, 40 patients, 20 of whom were subjected to mastectomy or quadrantectomy and 20 to inguinal hernioplasty, were randomly assigned to two treatment groups of 20 subjects each, balanced by type of operation. Treatment lasted 3 days and involved the administration of 3 suppositories per day of nimesulide or diclofenac sodium. Independently of the type of operation, a significant reduction in pain symptomatology (spontaneous pain, pain on active and passive movements) and in inflammatory symptomatology (hyperaemia and tumefaction) and a good control of body temperature was observed for both treatment groups. No changes in arterial pressure or laboratory examinations were observed in either group, nor there were any noteworthy adverse reactions.