Sixty outpatients with osteoarthritis of the interphalangeal joints of the hands or trapezo metacarpal joints were included in a multicentre, randomised, double-blind, parallel-group study. Patients were assigned to ibuprofen 800 mg (n = 30) or a placebo (n = 30) in two daily doses after morning and evening meals, for 14 days. Patients were assessed at entry and after one and two weeks' treatment. On D7, overall efficacy assessments performed by the investigator and patient using a four-point scale and overall spontaneous pain evaluated by the patient showed changes in favor of ibuprofen 800 mg. On D14, all selected evaluation criteria showed improved results with ibuprofen compared to placebo (p < 0.01). Three patients in the ibuprofen 800 mg group and one in the placebo group experienced adverse events during the study. Neither the incidence nor the type of adverse events were significantly different in the two groups. The algofunctional index recently developed by R.L. Dreiser and evaluated during this study correlated significantly with spontaneous global pain and with physician and patient efficacy ratings on D7 and on D14, but should nevertheless be subjected to a further validation study.