Hello, when the crab is dying or dying, the oxygen acid in the crab will decompose to produce histamine, which is a toxic substance. Even if the crab is cooked, this toxin is not easy to be destroyed. It is recommended that you do not eat it.
Suggestion:
Crabs are also rich in nutrition. The content of protein is several times higher than that of pork and fish, and the content of calcium, phosphorus and vitamin A is also very high. Try to eat crabs when you are alive.