We compared efficacy and safety of aspirin (ASA) and fenoprofen in the treatment of JRA. Ninety-nine children with JRA were given ASA or fenoprofen in a 12-wk, multicentered, double-blind, parallel study. Initial fenoprofen dosage was 900 mg/m2/d increased to 1800 mg/m2/d (3200 mg/d-max). Initial ASA dosage was 1500 mg/m2/d increased to 3000 mg/m2/d (5450 mg/d-max). Adverse reactions forced removal of 14% of ASA treated patients from the trial, whereas no fenoprofen patient was removed for this reason. Forty of 50 ASA patients, and 47 of 49 fenoprofen patients completed at least 10 wk of therapy and analysis showed that the 2 drugs were nearly identical in efficacy, but toxicity was considerably less among fenoprofen treated patients.