You cannot eat dead crabs. When a crab is dead, the histoxic acid in the crab's body will decompose to produce histamine. Histamine is a poisonous substance. As the death time prolongs, more and more histamine accumulates in the crab body, and the poisonous gas becomes more and more powerful. Even if the crab is cooked, this toxin is not easily destroyed. Excessive ammonia nitrogen must be excreted from the kidneys, so eating dead hairy crabs is very harmful to the kidneys. People who eat dead crabs may experience symptoms such as vomiting, abdominal pain, and diarrhea. Even half-dead "leg crabs" are not suitable for consumption.