Disclosed is a composition for preventing and treating acetaminophen induced liver injury including the protein extracted from Porphyra yezoensis. The protein(s), separated and purified from hot water extracts of Porphyra yezoensis, having the molecular weight of 14 kDa measured by sodium dodecyl sulfate polyacrylamide gel electrophoresis, has an excellent effect for inhibiting the oxidative injury of liver tissue and cell apoptosis of liver cells induced by acetaminophen.
