A comparative study between nefopam (Acupan) and pentazocine was carried out in 90 patients for treatment of postoperative pain following gynaecological operations. The results show that nefopam has an analgesic activity comparable with that of pentazocine, but its duration of action seems to be longer-lasting, even if with a longer period of latency. At equieffective analgesic action, nefopam shows a lower interference with the respiratory function. As far as side-effects are concerned a significant increase in drowsiness was observed with both types of treatment; sweating was observed only in nefopam group.