The effect of a single pre-operative oral dose of controlled release diclofenac sodium on post-operative pain after minor gynaecological surgery was investigated. Fifty-two women took part in a double-blind controlled study. Pain was assessed by visual analogue scale (VAS), a four-point verbal rating score, and the requirement for post-operative analgesia. Those patients who received diclofenac had significantly less post-operative pain than the placebo group up to 2 h after surgery.