Tenoxicam (Tilcotil, Mobiflex), a new non-steroidal anti-inflammatory agent of the oxicam group, has been compared at two dose levels (20 mg/day and 4 mg/day) to ibuprofen 800 mg t.d.s. in a double-blind parallel group study of four weeks duration in rheumatoid arthritis. Efficacy results showed no significant difference between the three treatments at two or four weeks though clinical assessments slightly favoured groups treated with tenoxicam in this 30 patient study. No patients withdrew from tenoxicam because of side-effects and there were no withdrawals because of inefficacy. The higher dose (40 mg) of tenoxicam was as well tolerated as the lower dose (20 mg) though plasma levels of tenoxicam suggested that at the lower dose this drug had barely reached optimum plasma levels in a study of relatively short duration.