any of various plants whose roots have been regarded as a remedy for snakebites, as the herb Aristolochia serpentaria(Virginia snakeroot), having a medicinal rhizome and rootlets, and the white-flowered Polygala senega(Seneca snakeroot), having a medicinal root.
British Dictionary definitions for virginia snakeroot
snakeroot
noun
any of various North American plants, such as Aristolochia serpentaria (Virginia snakeroot) and Eupatorium urticaefolium (white snakeroot), the roots or rhizomes of which have been used as a remedy for snakebite