Although the use of non-steroidal anti-inflammatory drugs (NSAIDs) is well established in the postoperative setting, their use after caesarean sections is still controversial. In a randomised, double-blinded, placebo controlled study we have estimated the opioid-sparing effect of diclofenac suppositories after elective caesarean sections in spinal anaesthesia. Eighty-two women ASA class I or II scheduled for caesarean section were randomised to receive either diclofenac suppositories 100 mg or placebo every 12 h after the operation. The diclofenac group (n = 40) consumed significantly less morphine in the postoperative period (14.0 +/- 1.5 mg in 32 h) compared with the placebo group (21.5 +/- 1.6 mg in 32 h, P < 0.05). The average level of postoperative pain as estimated by a visual analogue scale (VAS) and a verbal scale tended to be lower in the diclofenac group, but this was not significant. There were no differences in demographic data, perioperative bleeding, side-effects or discharge time between the groups. Diclofenac suppositories 100 mg given twice daily after caesarean section are opioid sparing. (C) 2002 published by Elsevier Science Ltd.