Fresh day lily contains a substance called colchicine, which will generate colchicine oxide when it participates in human metabolism. Colchicine oxide has a strong stimulating effect on human respiratory tract and gastrointestinal tract. The main symptoms are nausea, stomachache, diarrhea and even hematuria in severe cases. Therefore, the fresh day lily picked should not be eaten directly. In principle, it is recommended to steam the day lily to prepare for cooking. When eating, it is best for consumers to soak in clean water or warm water for many times before eating to remove residual harmful substances, such as sulfur dioxide. But fresh daylily should be blanched with water first, or cooked at high temperature, and then soaked in water for two or three hours before eating. For reference only!