According to SFGate, certain types of lilies are toxic to humans as well as animals, and should not be consumed under any circumstances. In some instances, consumption can land a person in the hospital or lead to death.
Not all lilies are poisonous, but a broad range of them can produce negative reactions. Toxic chemicals can be found in all parts of the flower, and in some cases the sap can cause skin irritation, according to SFGate. Lilies are particularly poisonous to cats and reactions can be especially severe. If a person or an animal experiences a negative reaction due to consuming or touching a lily, it is important to immediately call poison control and obtain a sample of the flower.