How did poison ivy evolve to produce a toxin?

All three of these plants produce urushiol, the compound that causes the itchy rash. People who chew the mango flesh from mango skins frequently get a blister rash on their lips. Pistachios also belong to this family but do not cause a rash. Poison oak and poison sumac are in the same genus as poison ivy. read more

Anyway, I do know that all plants produce a byproduct of metabolism, which is an acid. Mammals (including humans) do too, which is discarded in urine. Most plants leach the acid out through roots, leaves, or needles. But the Poison Ivy and Poison Oak, and others secrete the acid onto the leaves where it dries into crystals. read more

The difference between venom and poison is the way it gets inside the body. If it's injected like a snake bite or a bee sting, it's a venom. If it's eaten or contacted it's poison. Mushroom is poison, ivy is poison. Neurotoxin is a type of poison or venom. If it affects the nerves it is a neurotoxin. read more