(Business 2.0) – Poisonous venom from snakes, lizards, and snails is about the last thing you'd think of using as medicine. But it's what a growing number of pharmaceutical firms are basing new drugs on. "Just because something kills you at high doses doesn't mean it can't help you at lower doses," says Rik Deitsch, CEO of Nutra Pharma, a Boynton Beach, Fla., company whose scientists milk the venom of cobras with beakers. Once the toxins are removed, the venom's protein compounds can be used to treat HIV and multiple sclerosis. The medicine is certainly economical: 1 kilogram of modified venom could be enough to produce a million doses of a drug to treat HIV. (The drug is still in clinical trials.) Eli Lilly and Amylin Pharmaceuticals sell medication copied from the Gila monster's poisonous saliva to help diabetics control their blood sugar. It received FDA approval last year and is nearing a million prescriptions. Merck has anticlotting heart medication based on venom from the African saw-scaled viper, whose victims bleed to death. Elan, a biotech firm in Dublin, Ireland, offers a pain reliever called Prialt based on venom from an oceanic snail that paralyzes its prey. That's how to turn poison into profit.