Discussion and SummaryCytarabine, like other cytotoxic drugs, inhibits the onset of adjuvant-induced polyarthritis. Both steroidal and nonsteroidal “anti-inflammatory” drugs inhibit the severity of adjuvant-induced polyarthritis 6, 7, 20. The steroids are more effective, since they inhibit not only the onset and development of the disease, but also ameliorate its symptoms after it becomes well established. The current nonsteroidal antiinflammatory drugs are less effective than steroids on all parameters.Cytarabine, when compared to cyclophosphamide and phenylbutazone, has no “antiinflammatory” and antipyretic activity. It inhibits the draining lymph node hypertrophy which occurs after the inoculation of M. butymeum into the tail 19. Therefore, it may be added to the list of available cytotoxic drugs called “immunosuppressants.”Cytarabine is not effective at the doses used when given orally. It must be given parenterally. Cyclophosphamide and Medrol are effective by both routes.