Like all members of the buttercup family, winter aconite is very poisonous because all parts of the plant contain cardiac glycosides. When consumed in small doses by humans and other mammals, they stimulate the heart. When administered in substantial quantities, they may cause serious, often irreparable heart damage. Symptoms of poisoning include nausea, vomiting, diarrhea, disturbed vision, cardiac arrhythmia or, in severe cases, cardiac arrest.