Warfarin is a medicine that makes your blood less likely to form clots. It is important that you take warfarin exactly as you have been told. Changing how you take your warfarin, taking other medicines, and eating certain foods all can change the way warfarin works in your body. Warfarin (Coumadin ®) and Your Diet How does what I eat affect warfarin? Foods that are high in vitamin K can affect the way warfarin works in your body. Do remember though that Vitamin B12 doesnt absorb when you take it by mouth. It needs to be either an injected form or a sublingual form otherwise you are wasting your money. How to Take Coumadin®/warfarin Please take your pills as directed. You must take the pills only on the days your doctor or CAT Clinic nurse tells you to. Article by Laura Earl, RN, BSN, CACP. If you have been diagnosed with a blood clot, a medication named warfarin (Coumadin) may be prescribed as part of your treatment to prevent further blood clots. Why Vitamin K Can Be Dangerous if You Take Warfarin. Your diet affects how your medications work, especially for patients taking blood thinners such as Coumadin® (warfarin). Easy-to-read patient leaflet for Coumadin. Includes indications, proper use, special instructions, precautions, and possible side effects. Welcome. This site has been created to help you understand COUMADIN. We encourage you to learn all you can about taking COUMADIN and to use the tools we've provided to work with your healthcare provider to manage your treatment. Your free source for healthy, Coumadin (warfarin) safe recipes from Dr. Gourmet. Diet plans, nutrition information including vitamin K, and what you need to know to eat healthy while on Coumadin (warfarin). Warfarin (Coumadin® / Jantoven®) 1. What is warfarin (Coumadin® / Jantoven®)? Warfarin is an anticoagulant. Sometimes warfarin is referred to as a “blood thinner,” however;.