Since March 1941 I have had the opportunity to investigate a new synthetic analgesic drug, demerol,1 for the treatment of pain due to a variety of medical and surgical conditions. A year's experience has definitely indicated its value as an analgesic agent, and it was therefore deemed advisable to report on its effectiveness, potency and safety. In addition, its pharmacologic action in man relative to a comparison with morphine will be considered briefly. Eisleb and Schaumann2 introduced the drug in 1939 in an effort to obtain a synthetic substitute for atropine. However, it was soon noted on pharmacologic grounds that in addition to a slight atropine-like action on all smooth muscle, the drug possessed the unexpected effect of a morphine-like response on the central nervous system. Extensive pharmacologic and toxicologic studies have since been reported by Duguid and Heathcote3; Schaumann4; Gruber, Hart and Gruber,5 and