A short-term trial has been performed under double-blind conditions in 50 adult patients with rheumatoid arthritis to compare diclofenac sodium (Voltaren) with both indomethacin and placebo for efficacy and tolerability. The duration of the trial was two weeks and was a between-patient comparison of 25 mg t.i.d. diclofenac sodium, 25 mg t.i.d. indomethacin or placebo using a double-dummy technique. Forty-eight patients completed the trial. In the majority of parameters examined, diclofenac sodium was superior to placebo and indomethacin in therapeutic effect. One patient was withdrawn from the trial because of intolerance to indomethacin and one other because of severe joint pain under indomethacin therapy. Neither active compound caused clinically significant changes in blood picture or urine analysis.