The effect of daily, oral administration of ethanolic extract of Khaya senegalensis stem bark (2mg/kg body weight) for 18days on the alkaline phosphatase, aspartate and alanine aminotransferase activities of rat liver and serum were investigated. Compared with the control, the activities of liver alkaline phosphatase (ALP), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) increased significantly for the 6 and 18 days period of extract administration (P<0.05) without corresponding significant increase in the serum enzymes (P>0.05). The results indicate that the ethanolic extract of Khaya senegalensis stem bark has brought about induction of synthesis of the liver enzymes studied which is an important biochemical symptom of cytolysis.