A double-blind cross-over study was undertaken comparing the analgesic nefopam with the NSAID flurbiprofen in the treatment of osteoarthritis of the knees. Thirty patients entered the study and 18 completed the full trial protocol of one month on each drug. There was no significant difference in efficacy between the two treatments, although there were more side effects during the nefopam period. These must be balanced against the known gastrotoxicity of NSAIDs when choosing symptomatic treatment for osteoarthrosis.