American Medical Association in 1912 (Hender-

There is little question that all chemical substances capable of producing the state of anaesthesia may be classified as toxins. Such toxicity is within the limits of acceptability and is usually totally reversible. Depression of ventilation, cardiac function, CNS function and renal perfusion are recognized consequences of the state of general anaesthesia. These actions are ephemeral, dis-appearing soon after termination of administration of the inhalation anaesthetic. Obviously, reversible depression of organ systems is not imputed when toxicity of these drugs is mentioned. True organ toxicity is often irreversible, fatal and totally unexpected. Table I outlines some of the viscerotoxicities in which inhalation anaesthetics have been implicated. The theme of this review is viscerotoxicity initiated by biotransformation of the halogenated anaesthetics. Thus from a pragmatic standpoint, hepatic and renal viscerotoxicity of halogenated anaesthetics will be the primary focus of discussion. A BRIEF HISTORICAL BACKGROUND The first recorded case of unexplained jaundice following chloroform anaesthesia occurred in 1848 (Defalque, 1968), only 1 year after introduc-tion of this halogenated drug to clinical practice by Simpson. There was fairly widespread know-ledge that inhalation of chloroform could be followed in a small percentage of patients by "delayed chloroform poisoning". Ether was exonerated from this association. Continued difficulties with chloroform produced a prohibition of its use by the Committee on Anesthesia of th