Homoeopathic potencies of arnica have been used for many years to aid postoperative recovery. The effects of arnica C30 on pain and postoperative recovery after total abdominal hysterectomy were evaluated in a double-blind, randomized, controlled study. Of 93 women entered into the study, 20 did not complete protocol treatment: nine were excluded because they failed to comply with the protocol, nine had their operations cancelled or changed within 24 h and two had to be withdrawn because of the recurrence of previously chronic painful conditions. Those who did not complete protocol treatment were equally divided between the arnica (nine patients) and placebo groups (11 patients). 73 patients completed the study, of whom 35 received placebo and 38 received arnica C30. The placebo group had a greater median age and the arnica group had slightly longer operations; nevertheless, no significant difference between the two groups could be demonstrated. We conclude that arnica in homoeopathic potency had no effect on postoperative recovery in the context of our study.