Ragwort contains many different alkaloids, which makes it deadly poisonous to animals. In livestock if a sufficient quantity is consumed it can result in cirrhosis of the liver. Initial symptoms of poisoning can include yellow mucus membranes, depression, and lack of coordination. There is no known antidote or cure to poisoning in livestock.
Ragwort poses little risk to the livers of humans, although it is mildly poisonous. The alkaloids can be absorbed in small quantities through the skin but they are in the N-oxide form which only becomes toxic after conversion inside the digestive tract and they will be excreted harmlessly. Some individuals can suffer from an allergic reaction because ragwort contains sesquiterpine lactones which can cause compositae dermatitis.