Hepatic histopathology and clinical-pathologic correlations were studied in 77 patients who met clinical criteria for halothane hepatotoxicity. They were divided into groups based on the type of surgery (minor or major) and outcome (nonfatal, biopsy group or fatal, autopsy group). The two nonfatal groups (minor surgery and major surgery) and the two fatal groups (minor surgery and major surgery) were comparable with regard to age, time of onset from exposure, peak aminotransferase values and peak bilirubin determinations. A spectrum of histologic patterns was identified in these patients. It ranged from panlobular and multifocal spotty necrosis resembling viral hepatitis through submassive confluent zonal necrosis to massive necrosis. Progression of severity of injury from spotty to massive necrosis was more closely related to multiple exposures to halothane (and especially repeated exposure within less than three months), than to the extensive-ness of the associated surgical procedures.