SummaryClinical pharmacology and efficacy of benorylate in patients with rheumatoid arthritis. G. D. Champion, R. 0. Day, P. D. Paull, G. G. Graham, M. S. Owen, A. L Haski and L. Hills,Aust. N.Z. J. Med.,1978, 8, pp. 22–28.Benorylate, an ester of aspirin and paracetamol, was evaluated in 24 adult patients with rheumatoid arthritis. Benorylate dosage was individualized over a three week period, and subsequently, the patients were randomly allocated to continue dosage with benorylate or to change to placebo for one week. All measures of inflammation and pain worsened on the change to placebo. At the end of the double‐blind phase, significant differences were noted between the group who stayed on benorylate and the placebo group in the following parameters: pain index, articular index, functional index, the number of analgesic tablets taken, the duration of daytime rest and patients' and investigators' global assessments. There was no significant differences in the time to walk 50 feet while the differences in the duration of morning stiffness and grip strength were of marginal significance. The degree of relapse in the placebo group was most marked in patients who had attained plasma concentrations of salicylate above 130 μglml prior to the change to placebo. The mean adjusted daily dose of benorylate (±SD) was 11‐3 (±0–7) g and the mean plasma concentration of salicylate was 175 (