The influence of the nutritional status of the individual on the hepatic drug metabolising enzymes in human wedge-biopsy liver samples was investigated. The aryl hydrocarbon hydroxylase (AHH) was found to be elevated although there was no change in the cytochrome P-450 levels in the undernourished groups. Conjugating enzymes viz. UDP glucuronyl transferase (UDPGT) and glutathione-S-transferase (GST) were not found to be different. The increase in AHH activity as compared to UDPGT and GST activities suggests that the activation processes may possibly be increased in the undernourished segment of the population.