Veratrum is obtained chiefly from the rhizome and roots of Veratrum viride, an American plant, although the Veratrum album, a European plant, has also been used in medicine. Both varieties contain a mixture of alkaloids, the main action being due to protoveratrin. In the past, veratrum has been employed mainly as a cardiac depressant and to soften the pulse and lower the blood pressure in eclampsia.
According to Wood1 the effects of therapeutic doses on the circulation of mammals (dog and rabbit) consist of a slowing of the pulse and a moderate fall in blood pressure, the effects being rather persistent. The slowing is due mainly to stimulation of the vagus center (abolished by cutting the vagi). The vasomotor center is not stimulated except by the fall in blood pressure and by respiratory embarassment.
Toxic doses produce at first exaggeration of the vagus
COLLINS RJ. THE CLINICAL ACTIONS OF VERATRUM. Arch Intern Med (Chic). 1915;XVI(1):54-58. doi:10.1001/archinte.1915.00080010059004