A double-blind cross-over study is being undertaken in fifty patients with "definite" rheumatoid arthritis, comparing ketoprofen (2-(3-phenylbenzoyl proprionic acid) 75 mg daily orally and 100 mg suppository at night with indomethacin in the same dosage. A pilot study of twenty-four patients has been completed, fifteen having finished the trial. The objective assessment of grip strength and articular index were comparable with the two drugs, but subjective assessment showed that relief of early morning stiffness was better with indomethacin, although pain relief was no different. Evidence so far available shows that ketoprofen is a useful anti-inflammatory analgesic drug which is well tolerated and that the use of a suppository may be helpful in a few patients who find the oral route unacceptable. A larger study is necessary to evaluate finally the use of a combined administration.