I eat peppervine berries.
You probably shouldn’t.
While not toxic, they’re poisonous because the microscopic spines inside them can result in a chemical burn to the esophagus.
Almost everyone can eat one or two berries and have no problems. I know you can eat more if you’re willing to risk a burn and I think they’re a great survival food.
Personally, I’m not going to be chowing down because, although distantly akin to the grape, they aren’t worth very much throat pain–if any. I don’t eat very many.
And I’m sure my mother is happy about that.