Answer: veratrine

AnswerCrossword Clue
veratrinewhite or grayish-white, slightly water-soluble, poisonous mixture of alkaloids obtained by extraction from the seeds of the sabadilla: formerly used in medicine as a counterirritant in the treatment of rheumatism and neuralgia
veratrinean alkaloid or mixture of alkaloids obtained from white hellebore rhizomes, sabadilla, etc also VERATRIA, VERATRIN