Protection from carbon tetrachloride (CCL4)-induced hepatotoxicity by protein A was assessed histologically in rats. Carbon tetrachloride exposure produced swollen, vacuolated and necrotic cells in the centrilobular region of the hepatocyte in rats. Animals given protein A prior to and during CCL1 treatment showed a complete absence of hepatic lesions. Our study showed that protein A, a potent immunomodulator, has the potential to reduce liver injury caused by carbon tetrachloride, a known hepatotoxin in the rat.