It's called alloprotein reaction in medicine. A foreign protein simply means that it is not protein in one's body. Protein is a macromolecular substance, and protein, a heterogeneous substance, is a good antigen for human beings, which will cause hypersensitivity and produce allergy.

Many people with allergic constitution are allergic to certain foods in their daily life, such as eggs, fish, shrimp, crabs, grasshoppers, cicadas, silkworm chrysalis and other high-protein foods, prawns, crabs, Monopterus albus and other foods containing histamine, snails, grey vegetables, rape, safflower and other foods containing porphyrin sun-sensitive substances, while others are allergic to proteases in litchi and pineapple. There are many foods that can easily cause allergies, and the symptoms caused by various food allergies are different, and the clinical manifestations are complicated. After eating allergic food, some people will even have itchy skin, rash or fever, dizziness, nausea and vomiting immediately, which will induce bronchial asthma and lead to dyspnea. Some people will have symptoms of gastroenteritis such as drunkenness or abdominal pain and diarrhea. Therefore, when you have discomfort after eating, don't judge food poisoning easily, because it is probably an allergic manifestation of a food, which generally does not cause visceral damage and will not have any sequelae.