The Poison Ivy plant is a food source for animals; apparently the urushiol in the sap doesn't bother them but if the sap gets inside a human mouth it can cause a rash. I know how aggravating it was to have the rash on my arms and legs ... I can't even imagine how horrible it would be to have it inside my mouth! One lady who I volunteer with at the botanical gardens got it in her eyes a couple of years ago and ended up in the hospital! It was probably transferred from her gardening gloves or shirt sleeves.
