BACKGROUND: Intravenous patient-controlled analgesia (IV-PCA) is widely used because it is a simple, safe, and effective method for postoperative pain control. Controversies exist over the use of a continuous basal infusion in IV-PCA regarding its effectiveness. We evaluated the analgesic efficacy and side effects of PCA with basal infusion after gynecologic surgery and compared these results with PCA alone. METHOD: Eighty women undergoing elective gynecologic surgery under general anesthesia were studied. These patients were randomly assigned to receive either PCA alone (group 1) or PCA with basal infusion (group 2). Analgesic consumption, visual analogue scale (VAS) pain score, and side effects were assessed at postoperative 6 hours and 24 hours. RESULTS: In group 1, the amounts of analgesic used during the postoperative 6 hours and 24 hours were 15 +/- 5 and 30 +/- 13 ml, the median VAS pain score at postoperative 6 hours and 24 hours were 50 and 35 respectively. In group 2, the amounts of analgesic used during the postoperative 6 hours and 24 hours were 19 +/- 7 and 43 +/- 1 ml, the median VAS pain score at postoperative 6 hours and 24 hours were 50 and 38 respectively. The analgesic consumption during the postoperative 6 hours and 24 hours was significantly higher in group 2 than in group 1. There was no significant difference in median VAS pain score between the groups. There were no significant differences in incidence of side effects between groups. CONCLUSIONS: The use of a PCA with basal infusion appears to offer no clinical advantage over PCA alone.