Twenty-four male albino rats were used to evaluate the toxic effect of both single acute dose of paracetamol [500 mg/Kg body weight] and chronic dose [50 mg/Kg body weight] once a day for 20 days. Paracetamol [Pa] was injected intraperitonially according to animal body weight. The ultra-structural changes of peroxisomes guided by two marker enzymes were studied. Light microscopy showed marked hepatotoxicity due to paracetamol depending on dose and time. Electron microscopy showed different changes in peroxisomal shape and enzyme contents. The changes were more pronounced following the chronic dose of [Pa]. The study identified the possible mechanism with which liver cells can modulate cellular sensitivity to toxic effect of Pa. Oxidative stress was hypothesized to contribute to the initiation or progression of Pa-induced hepatic injury and showed that peroxisomes were highly dynamic important organelles numerous in the liver cells and that one of its main function is detoxification.