BROMOTRICHLOROMETHANE (CBrCl_3) treatment is a model for studies on molecular mechanisms of haloalkane toxicity with some advantages compared with CCl_4 treatment. The formation of 4-hydroxynonenal and similar aldehydic products of lipid peroxidation, which play a role as mediators of inflammatory processes, was clearly demonstrated in rat hepatocytes treated with CBrCI_3. It may be assumed that haloalkane toxicity is connected with the biological effects of those inflammation mediatory aldehydic compounds.