Naproxen tolerability in elderly patients was assessed using data from 9 double blind clinical trials. We analyzed the percentage of patients who (a) withdrew for complaints, (b) reported complaints, and (c) exhibited clinically significant laboratory test abnormalities. Among 1,178 patients with rheumatoid arthritis or osteoarthritis, 26% were 65 years old or older. These elderly patients demonstrated no consistent decrease in tolerability, or increase in toxicity, of naproxen, as compared with younger patients.