A single-blind, non-crossover study of the effectiveness of paracetamol, compared with aspirin and indomethacin has been carried out in 143 patients suffering from rheumatoid arthritis. Subjective indices have been employed, and the validity of the present method is discussed. The results of the trial have also been compared with those of a previous study (of prednisone, aspirin and placebo). Paracetamol was not significantly different from placebo, either in terms of pain relief or patient satisfaction rating. Prednisone and indomethacin were significantly better than paracetamol in respect to both parameters, but aspirin was not. On the basis of these results, the frequent prescription of paracetamol as the main therapeutic agent in the treatment of rheumatoid arthritis is not justified.