Objectives: To evaluate the analgesic efficacy and safety of diclofenac potassium in patients after dental surgery. Methods: Eighty patients with moderate to severe pain following extraction of one impacted third molar were equally and randomly divided to receive diclofenac potassium or diclofenac sodium 50 mg tid po for 3 days. Results: The quick efficacy rates of diclofenac potassium or diclofenac sodium were 55% and 15% respectively, and the cure rates were 95% and 73% respectively. The quick efficacy rate and cure rate of diclofenac potassium were statistically superior to diclofenac sodium ( P 0.05). Side effect rates of diclofenac pota ssium and diclofenac sodium were 5% and 7.5% respectively. Conclusions: diclofenac potassium is an effective and safe agent for treatment of pain following dental surgery.