I once read a blog post by a plant breeder who was crossing domestic and wild tomatoes to develop tomato varieties that could produce a crop in climates where our current varieties don't grow.

Most of the poisonous compounds in tomatoes have a bitter flavor, so he got pretty good mileage out of tasting a tiny amount of a fruit and not continuing if it had a bad taste. But one time he ate a very tasty little tomato he'd bred, and then several hours later started feeling really sick. For some reason he wrote "sorry" and the identifying info of the poison fruited plant on himself and went to bed instead of seeking medical help. (He may have been living off grid in a remote place or something like that, I don't remember.) Luckily he wasn't too badly poisoned and lived to tell about it.

For anyone interested in plant breeding, modern domestic tomatoes don't have the genes for poison fruit anymore, so you can crossbreed them with each other safely.