1832 H. Howard II. 360 Poolroot, White Snake-Root... The root is small, fibrous, of a dirty white, from two to four inches long... The root of this plant is the part used in medicine. It appears to be a warm stimulating tonic.
1869 W. Cook 418 Eupatorium Ageratoides. White snakeroot, pool root.
1941 E.L. Moseley xiv. 146 The plant that causes Milk Sickness has many names—White Snakeroot, White Sanicle, Indian Sanicle, Richweed, Deerwort, Boneset, Whitetop, Squawweed, Steria, Poolwort, Poolroot.