The SUR 2647 combination is a sachet formulation containing free paracetamol and its N-acetyl-methionate ester (SUR 2647). In a randomized, single-blind, between-patient study the onset of analgesia, duration and efficacy of the SUR 2647 combination vs paracetamol was investigated in out-patients after oral surgery. One group (n = 27) received sachets of SUR 2647 combination 2 b.i.d. (equivalent to 2 g paracetamol X 2) on the day of operation, and one sachet b.i.d. (equivalent to 1 g paracetamol X 2) for the following two days. The other group (n = 26) received paracetamol tablets 2 q.i.d. on the day of operation (1 g X 4) and one tablet q.i.d. (0.5 g X 4) for the following two days. Several objective and subjective assessments, including pain score on a visual analogue scale, were recorded for comparison of the postoperative courses. Median onset of analgesia for both groups was less than or equal to 0.5 h. The duration after SUR 2647 combination was greater than or equal to 5.5 h as compared to greater than or equal to 2.5 h for paracetamol. Mean pain scores showed that the SUR 2647 combination regime reduced pain significantly more than the paracetamol regime from 0.5 to 3.0 h after initiation of medication. The mean pain scores did not show a significant difference during the remaining observation period. Mild to moderate drowsiness was reported in both treatment groups, but it was more common in subjects given SUR 2647 combination.