One hundred and thirty-four patients with either osteoarthritis or rheumatoid arthritis, and with a history of current or past non-steroidal anti-inflammatory drug (NSAID) treatment, were interviewed regarding the benefits, expectations and side-effects of NSAID therapy. Their willingness to accept risks in medical treatment was also evaluated. Both groups experienced positive effects of the NSAID treatment corresponding to their expectations. However, rheumatoid arthritis patients were significantly more willing to accept gastrointestinal side-effects when given an effective NSAID than the osteoarthritis patients, and they were also more willing to take risks in trying a hypothetical new NSAID that had been shown to be effective in clinical trials.