The plant begins growing in late spring or early summer. The dogbanes contain cardiac glycosides that have physiologic actions similar to digitoxin. Dogbane's principle toxin has been identified as cymarin, which was once used as a heart stimulant for humans. Death from poisoning generally occurs 6 to 12 hours after animals eat the plant. Both dried and green plants are toxic.
Leaves are poisonous at all times, even when they are dry.
This includes emetics in species that can safely vomit, atropine treatment if the animal has bradycardia, activated charcoal and possibly cathartics to minimize absorption, and electrolyte therapy to correct any electrolyte imbalances. Research results suggest that hemp dogbane may be controlled by repeated treatment of 2,4-D at 0.5 to 2 Kg per acre of acid equivalent. Follow recommendations and precautions when handling herbicides.