There have been over 3,500 cases of Reye's syndrome reported to the CDC since 1973. The temporal use of aspirin with a prodromal viral illness has been statistically associated with the etiology of the syndrome. Reye's syndrome presents as an acute progressive encephalopathy with varying levels of coma and normal cerebrospinal fluid (CSF). Hepatic transaminases are elevated, and the serum aspartate aminotransaminase (AST) is usually elevated three to 30 times normal. Histological changes on liver biopsy are characterized by microvesicular intrahepatocyte lipid deposition, which is rarely found in other diseases. The syndrome has rarely been reported to occur in adults over 18 years old. We report the 25th case of Reye's syndrome occurring in an adult, which initially presented as acetominophen toxicity but was shown to be Reye's syndrome on histological examination of the liver.