The objective of this study was to investigate the effects of Mangifera indica L. (mango) stem bark crude Aqueous Extract (AE) on the morphology and biochemical functions of the liver in wistar rats. Adult wistar rats used in the study were divided into 2 groups: Group 1 rats were untreated and served as control and Group 2 experimental rats were orally given 1 mL (100 mg) daily of aqueous extract for a period of 14 days. The body weight changes and the weight of the liver were measured and the serum aspartate aminotransferase (AST), Alanine Transaminase (ALT), Alkaline Phosphatase (ALP), Total Bilirubin (TB) and Conjugated Bilirubin (CB) levels were determined. There was no significant difference (p<0.05) in body weight gain between the two groups at the end of the experiment. The treated group had a significant decrease in liver weight (p<0.05) when compared with control. The treated group also had a significant increase in AST when compared with control. There were no significant increases in ALT, ALP and total bilirubin when compared with the control. The study suggests derangement of liver function and possible damage to the hepatocytes by the crude AE at this dose and duration.