Vitamin k

In biochemistry and medicine, vitamin K is an essential nutrient that is "lipid cofactor that is required for normal blood clotting. Several forms of vitamin K have been identified: vitamin K 1 (vitamin K 1) derived from plants, vitamin K 2 (menaquinone) from bacteria, and synthetic naphthoquinone provitamins, vitamin K 3 (menadione). Vitamin K 3 provitamins, after being alkylated in vivo, exhibit the antifibrinolytic activity of vitamin K. Green leafy vegetables, liver, cheese, butter, and egg yolk are good sources of vitamin K." Vitamin K 1 is also called phytonadione.

In medicine, vitamin K is used to both reverse the effects and steady the effects of warfarin.