[8] It is used to treat certain bleeding disorders,[7] including warfarin overdose, vitamin K deficiency, and obstructive jaundice.

[7] Many countries in the world choose intramuscular injections in newborn to keep them safe from vitamin K deficiency bleeding.

[7] Severe allergic reactions may occur when it is injected into a vein or muscle, but this has mainly happened when large doses of a certain type of supplement containing castor oil were given intravenously.

[18][19] The best-known function of vitamin K in animals is as a cofactor in the formation of coagulation factors II (prothrombin), VII, IX, and X by the liver.

The conversion of chorismate to vitamin K1 comprises a series of nine steps:[22][23][24] In Canada, phytomenadione (Hemophyt) is indicated for the treatment of anticoagulant poisoning in dogs.