Once you've been bitten, it only takes a few seconds for the venom to travel from the fangs through your skin and into your bloodstream. You'll notice symptoms right away, and they'll worsen over time. The venom will cause tissue damage and circulatory system failure by damaging blood cells and causing internal hemorrhaging. Rattlesnake venom is mostly a mixture of hemotoxins, which are poisons that disrupt blood vessels and blood-clotting, and neurotoxins, which cause nerve and muscle paralysis. If the wound is not treated, your bodily functions will shut down over the course of three days, and the bite may cause severe organ damage or worse.