Tremetone and structurally related compounds in white snakeroot ( Ageratina altissima ): a plant associated with trembles and milk sickness.

Ingestion of white snakeroot ( Ageratina altissima ) can cause trembles in livestock and milk sickness in humans. The toxicity has been associated with tremetol, a relatively crude, multicomponent lipophilic extract of the plant. In this study, 11 different compounds were isolated from white snakeroot-derived lipophilic extracts from 18 collections. Six of the isolated compounds have not been previously reported to be found in white snakeroot. High-performance liquid chromatography (HPLC) analysis indicated that there are three different chemotypes of white snakeroot from the plant samples analyzed. Elucidation of these chemotypes may explain the sporadic and unpredictable toxicity of white snakeroot to livestock and humans.