Ok this one is way out in left field, kinda goofy, and is just for fun. With bath salts and people eating each other recently, it appears a Zombie Apocalypse may or may not be upon us. Ok, maybe not, but more realistically, imagine you end up stranded for weeks in the wilderness. You have no access to your prescription of aspirin (in my case with a tissue valve) or Coumadin. I know that these drugs may have some natural extracts, and there are naturally occurring blood-thinners in the wild. Of course it would be dangerous and stupid to switch to herbal alternatives without consulting a doctor, but what could you find in nature if no alternative was present? Disclaimer: Most of us are not doctors and the info could be totally wrong, but it is an interesting question, if you can find any info.