Phytomenadione is a procoagulant factor. As a component of a hepatic carboxylase system, Phytomenadione is involved in the post translational carboxylation of clotting factors II (prothrombin), VII, IX and X and the clotting inhibitors protein C and protein S. Phytomenadione is ineffective in hereditary hypoprothrombinemia or hypoprothrombinemia induced by severe hepatic failure. Lack of Phytomenadione leads to an increased tendency to haemorrhagic disease in the newborn. Phytomenadione administration, which promotes synthesis of the above-mentioned coagulation factors by the liver, can reverse an abnormal coagulation status and bleeding due to Phytomenadione deficiency.