Following acute thermal injury to rats produced by scalding water, there was marked elevation of a number of plasma enzyme activities, including GOT, GPT, and 5'-nucleotidase, suggesting hepatic dysfunction. Changes in plasma enzyme activities were observed within minutes following application of acute burn trauma, and remained elevated for at least one month. The magnitude of the elevations of the plasma enzyme activities was dependent upon the length of time the acute burn trauma was applied to the skin and/or the percentage of skin surface area burned. These changes in plasma enzyme activity correlated with histologic examination of the hepatic tissue, indicating single cell necrosis. These data suggest that acute burn trauma to rats is associated with altered hepatic function.