Crayfish is not poisonous. Whether the heavy metals in crayfish exceed the standard is really related to the living environment of crayfish. However, it is unscientific to say that "the problem of excessive heavy metals in crayfish is serious, and it will be poisoned if eaten too much". Crayfish contains very little heavy metals, so it can be safely eaten. Crayfish is delicious and nutritious. Pay attention when eating, the body is soft and inelastic, and it is probably dead shrimp. When buying crayfish, I am most afraid of encountering dead shrimp, because crayfish will rot quickly after death, decompose and produce toxic substances such as histamine and breed harmful bacteria. After eating, it is easy to cause gastrointestinal infectious diseases such as diarrhea, which is harmful to health. Precautions for expanding data to eat healthy crayfish: 1. Buy in the regular market and choose crayfish with big head, green shell and strong vitality. 2. Before cooking, you can put it in clear water, spit out impurities such as silt in your body, cut off shrimp cheeks and claws, brush shrimp shells with a brush, and steam them when cooking. When eating, you must pay attention to peeling the shell, removing the head and removing the internal organs. 4. Don't eat with persimmon, pomegranate, grape, hawthorn and other fruits to prevent tannic acid in these foods from forming insoluble substances with calcium in shrimp, causing gastrointestinal discomfort.