The interaction of chemicals (e.g. drugs and pesticides) with the biological system may be a complex phenomenon and is ultimately an expression of the interplay between the environment, the host and chemical substance. It is evident from the literature, which is extremely limited, that drug/insecticide interactions may result in altered response/toxicity, which is of clinical relevance. Thepresent study was conducted to evaluate the adverse effect of exposure to diazinon (DIA) and paracetamol (PARA) and their combination on liver of male rats. Rats were orally administered PARA at a dose of 66.66 mg a.i. kg-1 weight (maximum administration dose) and DIA at a dose 12.50 mg a.i. kg-1 b.wt. (1/100 LD50) for 28 consecutive days. Significantly, decreasedbody weights were observed in all treated groups, while significant increase in relative liver weight were recorded in DIA andDIA+PAQ-@treated groups compared to control rats. Liver dysfunction enzymes (e.g., aspartate aminotransferase, AST; alanineaminotransferase, ALT; alkaline phosphatase, ALP and lactate dehydrogenase, LDH) and lipidperoxidation level (LPO) were increased in DIA, PARA and DIA+PAQ-@treated groups. Treatment of DIA and DIA+PARA caused significant decrease in theactivity of serum cholinesterase (ChE). PARA, DIA and PARA+DIA treatments caused histopathological changes and decreasein DNA content in liver cells of rats. The severities of such observations were more pronounced in their combined exposure. We can conclude that both paracetamol at maximum administration dose and diazinon caused biochemical and histopathological alteration within the liver of male rats. The severities of such observations were more pronounced in their combined exposure. The data throw light on the matter of simultaneous exposure to OPIs and commonly used drugs especially among agriculture sector workers in developing countries, where the handling of medicine (e.g., PARA) is mainly without medical prescription. Further studies, applied to pregnant women, newborns and childhood may be of great significance.
