na your body can break down alot of poisons as long as they have the antibodies required so your immune system targets it.
but certain ones it doesn't matter you have to chemically counter it
edit-
http://en.wikipedia.org/wiki/Antidote{The antidotes for some particular toxins are manufactured by injecting the toxin into an animal in small doses and extracting the resulting antibodies from the host animals' blood. This results in an antivenom that can be used to counteract poison produced by certain species of snakes, spiders, and other venomous animals. A number of venoms lack a viable antivenom, and a bite or sting from an animal producing such a toxin often results in death. Some animal venoms, especially those produced by arthropods (e.g. certain spiders, scorpions, bees, etc.) are only potentially lethal when they provoke allergic reactions and induce anaphylactic shock; as such, there is no "antidote" for these venoms because it is not a form of poisoning, though anaphylactic shock can be treated (e.g., by the use of epinephrine).}
This post was edited by Garethsir on Feb 22 2009 09:32pm