The efficacy, tolerance, and safety of CPH 82 (semisynthetic lignan glycosides) (Conpharm AB) for patients with rheumatoid arthritis (RA) were assessed in a 12-week double-blind placebo-controlled study. Thirteen patients out of 15 in the CPH 82 group and 10 out of 15 in the placebo group completed the study. No improvement was seen in placebo treated patients. Patients treated with CPH 82 showed a statistically significant improvement in most clinical and immunological variables. Some patients treated with CPH 82 reported gastrointestinal discomfort (diarrhoea and abdominal pain).