In a randomized double-blind study 60 children, undergoing the extraction of carious deciduous teeth under day-case general anaesthesia, were assigned to receive either intravenous nalbuphine hydrochloride 0.3 mg kg−1 (n = 21), one or more diclofenac suppositories 12.5 mg to a dose of 1–2 mg kg−1 (n = 19), or no analgesia (n = 20). The duration of anaesthesia was longer in the diclofenac group (9.6 min, SD 3.5) compared with control (7.2 min, SD 2.6) and nalbuphine (6.9 min, SD 3.0) groups respectively (P < 0.05). There were no statistically significant differences in post-operative pain scores during the 45 min post-operative period studied between the three groups using an objective pain score. We conclude that using this methodology we were unable to demonstrate any statistically significant differences between the analgesic effects of either intravenous (i.v.) nalbuphine or diclofenac suppositories compared with control.