The head of crayfish is inedible. The circulatory system, respiratory system and reproductive system of shrimp are concentrated in the head and chest, and the abdomen can be said to be just a motor organ. There are not only many formed eggs in the head of shrimp, but also many other crayfish's own garbage toxins. The head of lobster is very easy to absorb heavy metals and toxins. For these reasons, eating the head of crayfish may cause allergies and acute gastroenteritis, and the head and neck of lobster may cause paragonimiasis.