The analgesic effect of 10 anti-inflammatory drugs was compared using a single-blind method in 90 patients with rheumatoid arthritis. Each patient received two different drugs, for three days each and each drug was evaluated in 18 patients. After the trial, the patients considered which of the drugs they preferred. The greatest relief from pain was achieved by diclofenac, indomethacin, naproxen and tolfenamic acid, each of these being preferred by the majority of patients and being significantly (p>0.01) better than the least effective drugs ketoprofen and proquazone. Acetylsalicylic acid, azapropazone, carprofen and ibuprofen were considered intermediate in efficacy.