The effect of polychlorinated biphenyls (PCB), phenol and biphenyl on the body, liver and kidney weights, and the activity of $delta$-aminolevulinic acid dehydratase (ALAD), and the contents of microsomal cytochrome P-450, and hematocrit, TBAvalue. PCB (200 mg/kg), phenol (200 mg/kg), biphenyl (200 mg/kg), and biphenyl (100 mg/kg) added phenol (100 mg/kg) was treated orally to Sprague-Dawley rats for 3 days. In all treated groups, the body weights were decreased, while the weights of liver and kidney were increased in comparison with that of control group. The activity of $delta$-ALAD was increased and hematocrit was decreased in PCB treated group, on the contrary biphenyl treated group was appeared opposite direction. The contents of microsomal cytochrome P-450 and concentration of protein were increased in all treated group. In biphenyl treated group and phenol treated group, TBA value was increased in both groups.