Studies were made on the effect of protoporphyrin in treating the acute liver injury induced by carbon tetrachloride ( CCl4 ) in rabbits and on the liver blood flow, biosynthesis of DNA and protein in liver of mice. The results showed that the protoporphy-rin was able to protect the liver remarkable as evidenced by his-tological studies. And it could inhibit the elevation of serum glut-amic-pyruvic transaminase ( SGPT ) , serum glutamic - oxaloacetic transaminase ( SGOT ) and serum ?-glutamyl- transpeptidase ( S?- GT)also. Protoporphyrin could regulate the metabolism of serum amino -acids in rabbits intoxicated by CCl4 as well. Furthermore,protoporphyrin can improve biosynthesis of DNA and liver protein and it may increase the blood flow in the liver of the mice.