Levels of lipid peroxides in rat caecum, blood, liver and kidney and the capacity of tissue homogenates to form lipid peroxidesin vitro was enhanced after caecal amoebiasis in rats produced byEntamoeba histolytica (IB-1). The activity of hepatic drug-metabolizing enzymes in post-mitochondrial fraction and the cytochrome P450 contents in microsomal fraction decreased significantly, while lysosomal enzymes such as acid phosphatase, acid ribonuclease and cathepsin B showed an increase in the liver homogenates of infected animals. These changes were reversed following treatment with the antiamoebic drug, metronidazole
