A double-blind controlled cross-over trial comparing floctafenine 1.6 g daily with soluble aspirin 4.0 g daily and matching placebo, in 48 patients suffering from rheumatoid arthritis, is reported. Floctafenine and aspirin gave statistically significant reduction in morning stiffness, grip strength and better subjective assessment than the placebo. There was no difference in the relief of pain between the three treatments under the conditions of this trial where paracetamol was allowed as an additional escape analgesic. During the period of aspirin therapy there was a higher indicence of concurrent complaints, faecal occult blood loss and a reduction in haemoglobin. An open long-term study in 12 rheumatoid patients receiving floctafenine 1.6 g daily for 3--6 months showed satisfactory management of their clinical condition. There were no significant or serious side-effects or change in biochemical or haematological parameters, and patients completed their course of therapy.