For allergy after eating crabs, patients can choose different medications according to different allergic symptoms, and in critical cases, other medical means are needed to assist the treatment. For mild allergic reactions, such as mild nausea, vomiting, abdominal pain, diarrhea and other gastrointestinal symptoms, oral antihistamine drugs such as cetirizine, chlorpheniramine maleate, loratadine, etc. can be taken to alleviate the allergic reaction on the premise of stopping eating, and antidiarrheal, antiemetic drugs such as montelukast and metoclopramide hydrochloride can also be taken to accelerate the discharge of the allergic substances and alleviate the symptoms. Severe allergic reaction may be manifested as a sharp drop in blood pressure, dyspnea, loss of consciousness or anaphylactic shock, etc. Eating should be stopped immediately and fasting treatment should be given, meanwhile, timely application of epinephrine, infusion of glucocorticoids and other anti-allergy, anti-shock treatment should be given, in addition to respiratory management should also be carried out immediately to prevent asphyxia. For crab allergy patients, need to be vigilant when eating other seafood, can do allergen check.