Drug withdrawal rate and reasons for treatment termination were studied in a retrospective life-table analysis of patients with rheumatoid arthritis prescribed Proresid, a semisynthetic podophyllotoxin derivative. Two years after starting with Proresid medication, half of the patients were still on treatment. After 5 years the termination rate had risen to 71%. Gastrointestinal side effects were the most common reason for abandoning medication. The results are compared with those found in other studies of similar desing. It is concluded that Proresid is a valuable and well-tolerated disease-modifying drug for long-term treatment of rheumatoid Arthritis.