The poison is a volatile alkaloid, coniine, found in the foliage all season and in the seeds in late summer. Most livestock poisoning comes in the spring from eating fresh foliage. 18 Mayapple, bloodroot, pokeweed, nightshade and hellebore are other alkaloidal plants. They are rarely eaten except when animals are starving for better feed. Deaths from alkaloidal plants usually result from severe digestive disturbances, pain and nervous symptoms.
Animals usually die in convulsions.
This means photo-sensitive animals get a reaction. In typical cases, an animal suddenly becomes sore on the white areas of their bodies. Whole areas of white skin may raise up and slough off. White goats may become severely affected and die from this condition. Some common plants which cause photosensitization are rape, alsike clover, buckwheat, lantana, St. John's wort, and ornamental hypericums.