Thirteen biochemical parameters (viz. glucose, calcium, inorganic phosphorous, urea nitrogen, uric acid, cholesterol, albumin, total protein, total bilirubin, alkaline phosphatase, lactate dehydrogenase, aspartate aminotransferase, and alanine aminotransferase) were determined in serum and partly in liver of rats 1-28 days after i.p. aflatoxin B1 (AFB) (3 mg/kg). Histological examinations of the liver were also made in parallel to the biochemical studies. In the serum, enzyme activities and total bilirubin level increased and peaked on the 2nd day, while other activities of aspartate aminotransferase and alanine aminotransferase in the liver significantly decreased and reached a minimum on the 2nd day after AFB administration. The depression of the liver enzyme activities persisted over 7 days. The liver protein content also reduced transiently during 1-1.5 days. However, all biochemical parameters returned to normal levels 2 weeks after treatment, and remained so throughout the rest of experimental period. Histological changes in the liver were very similar to those reported by other.