Bittersweet is a climber, a pretty one with its blue or violet flowers, and, in time, berries that go as the season progresses from shiny green to bright red. The flowers hang down in drooping clusters, each flower showing a yellow beak at its center. The plant is sometimes called "deadly nightshade." This is because the leaves and the unripened, fruit contain alkaloid solanine. ("The alkaloids act most powerfully on the animal economy; some, such as strychnine, nicotine, &c., form the most violent poisons with which we are acquainted, whilst others, such as quinine and morphine, act as most valuable medicines." -- As quoted in the OED.) We read in Audubon that "the toxin is not normally fatal." The Bittersweet was used in England to counter the effects of witchcraft.