Recent toxicological and chemical investigations1 of richweed poisoning, supported by a large number of clinical reports of cases of milk sickness, make it possible to state definitely certain facts about this disease. It can no longer be doubted that milk sickness is richweed poisoning and that it is caused by the consumption of milk or milk products obtained from cows that have fed on that plant.2 Richweed, or white snakeroot, known botanically as Eupatorium urticaefolium Reich., is one of the composite family. It occurs throughout the eastern United States as far west as Oklahoma and Nebraska. A chemical study of the toxic constituents of this plant has revealed the fact that three poisonous substances are present. Two of these, a volatile oil and a resin acid, do not produce "trembles" in animals and have no relationship to milk sickness. The third poison is an oily liquid, with the