Warfarin, a drug that many people must have heard of, is mainly used to combat diseases such as thromboembolism. It works by inhibiting the synthesis of clotting factors in the liver, which is involved in vitamin K, to achieve anticoagulation. Warfarin has no effect on existing clotting factors and must be used only after the relative depletion of clotting factors in the body, so it is slow to take effect and lasts longer after discontinuation. Vitamin K is a group of substances with the biological activity of chlorophyll quinone, which can promote normal blood clotting and reduce the risk of fracture. The intake of large amounts of vitamin K in a short period of time can inhibit the effect of warfarin, so when taking warfarin, care should be taken to avoid consuming large amounts of vitamin K-rich foods such as green leafy vegetables, vegetable oils, meat and milk, and less cereals and fruits in a short period of time. Vitamin K in food is fat-soluble and is mainly absorbed into the lymphatic system by the small intestine. 40-70% of vitamin K can be absorbed by people with normal gallbladder and pancreas function. The human intestine has a bacteria that can continuously produce vitamin K. Together with the intake of green vegetables, animal liver, eggs and dairy products, the average person will not be deficient; however, those who use antibiotics and other things that lead to intestinal flora imbalance may have a relative deficiency of vitamin K. Healthy people need less vitamin K, but it is significant to reduce bleeding in patients with internal bleeding, nosebleeds, excessive physiological bleeding and hemorrhoids. Vitamin K is not yet included in the Chinese food composition list, and no specific values are available at this time. Only some common foods in the United States are available for reference. Chlorophyll quinone content in common foods in the United States Food name Chlorophyll quinone Food name Chlorophyll quinone Spinach 380 Dried lentils 22 Lettuce 315 Liver 5 Cabbage 145 Egg 2 Asparagus 60 Fresh meat <1 String beans 33 Fresh fish <1 Peas 24 Whole milk <1 Cucumber 20 Soybean oil 193 Broccoli 20 Cottonseed oil 60 Carrots 10 Olive oil 55 Tomatoes 6 Corn oil 3 Potatoes 1 Vegetable butter 42 Dried soybeans 47 Cream 7