The objective of this paper was to evaluate serum glutathione S-transferasethe (GST) in thioacetimide (TAA)-induced hepatotoxicity in mice. The results showed that intraperitoneal injection of TAA (25-100 mg/kg) increased serum GST activity. The activity of GST was dose- and time-related to TAA. There was a good positive correlation between serum GST and serum alanine transaminase(ALT) activities. The content of reduced glutathione(GSH) and activities of GST, glutathione peroxidase(GSH-Px) and superoxide dismutase(SOD) were significantly decreased while serum GST activity induced by TAA was high. The results suggested that the reduced hepatic antioxidative function is one of the mechanism of TAA-induced hepatotoxicity, and serum GST activity is a sensitive and early marker in detecting TAA-induced hepatotoxicity.