Will this product thin the blood too much at 400 IUs per day? Or can it replace the Warfarin (Coumadin)?? This question should be discussed with your primary health care professional. If you do not have a doctor to discuss this with, we may be able to direct you to one of our doctors that understand how vitamin E interacts with various blood thinning medicines such as Coumadin/Warfarin. Vitamin E is a natural blood thinner, so it is very important that since you are presently taking prescription medicine for this, that you discuss your options with a healthcare professional that can advise you correctly. If you do not have a doctor or nutritionist that you can talk to, we may be able to suggest one of our trusted partners in your area.