Toxic wood effects

So I live way out here in the desert. There's literally acres of velvet mesquite growing everywhere. There's some other trees too, some of which aren't any good for smoking. Now I have educated myself as well as I can using Google to identify the tree including comparing them to known examples. Some of these trees are standing dead falls meaning they are way dead but haven't collapsed yet. But they are super dry. But just to make sure and cover my bases the best I can, has anyone used the way wrong tree and gotten sick? If so what were the symptoms? I burned a little bit of the wood and it smells great. It's probably mesquite, but if it's not I'm trying to understand what being sick from using the wrong wood is like. Fall down dead? Meat tastes like everything bad? Sonic diarrhea? Horror movie vomiting? All or none of the above? I've called a couple hospitals thinking they might know, they don't even understand the question...