> << I'm pretty sure there's something useful out there. Perhaps
Puffer fish poison is not a non-lethal toxin. You have to be extremely careful about dosage. A little too high and the person dies a quick and horrible death. Check out stories on fugu poisioning. Interestingly the fish do not directly produce the poison (those raised from eggs in captivity are non-poisonous - it is created by symbiotic bacteria. For those Australians on the list this same bacteria produce the poison used by blue-ringed octopus (though in this case the octopus actually collects the toxin in its poison fangs).
Have a look at:
for some case histories of poisoning.