100 male Wistar albino rats were used in this study. After the adaptation period, the rats were divided into 5 equal groups. The experimental period lasted 22 days. Food and water were given ad libitum. 0 ppm. 100 ppm, 500 ppm, 1,000 ppm and 2,000 ppm zinc were given by nasogastric probe to the control, experiment-1, experiment-2, experiment-3 and experiment-4 groups respectively, on days 1, 6, 11, 16, and 21 of the experimental period. The animals were weighed and blood samples were taken on days 2, 7, 12, 17, 22 of the experimental period. AST, ALT and ALP levels in sera were determined by spectrophotometric methods.