Many people think that the entire crab is poisonous, but this is not true! Only certain parts of the crab are poisonous. The most poisonous part of the crab is the liver, which contains a toxin called paralytic shellfish poisoning (PSP). This toxin can cause paralysis and even death if ingested in large enough quantities. Other parts of the crab that contain smaller amounts of PSP include the gills, stomach, and intestine. So, if you're ever planning on eating crab, make sure to remove these parts before cooking!