Very poisonous. Two berries and you're done. Bittersweet nightshade
Solanum dulcamara, also known as bittersweet, bittersweet nightshade, bitter nightshade, blue bindweed, Amara Dulcis,climbing nightshade, fellenwort, felonwood, poisonberry, poisonflower, scarlet berry, snakeberry,trailing bittersweet, trailing nightshade, violet bloom, or woody nightshade, is a species of vine in the potato genus Solanum, family Solanaceae. It is native to Europe and Asia, and widely naturalised elsewhere, including North America, where it is an invasive problem weed.