This study evaluated the efficacy of diflunisal as an analgesic to reduce postoperative pain when administered immediately following periodontal surgery. It was a continuation of a previous investigation which tested the effectiveness of diflunisal, administered preoperatively, in reducing periodontal surgical pain. Twenty-four patients were divided into two groups in a double-blind, random manner. Group 1 received postoperative therapeutic doses of diflunisal equal to the preoperative doses administered in the first study, and Group 2 received postoperative placebos. The postoperative diflunisal group reported significantly less pain (P less than or equal to 0.05) than the postoperative placebo group, and used rescue medication significantly less often (P less than or equal to 0.05). There was no significant difference in postsurgical discomfort between diflunisal administered postoperatively in this study and equal dosages of diflunisal administered preoperatively as previously reported.