Some heart and blood vessel diseases cause blood flow to be poor so blood thinners are prescribed. Blood thinners are used to reduce risks for heart attack and stroke. Thinners are also used for those who have had heart surgery or suffer from atrial fibrillation. The two main categories of blood thinners are anticoagulants and antiplatelets. One lengthens blood clot time and the other prevents any sort of clumping. The challenge with blood thinners is finding the right dose and keeping that level consistent. Deviations in diet, while on blood thinners, at any time can cause issues from feeling tired to bleeding to death. Needless to say, it's important to understand how blood thinners will affect you and your lifestyle.