Blood transfusions generally have few hazards, but some hazards such as fever, allergies, and risk of disease transmission can occur if they are not done properly or if the patient has a special health condition of his or her own. Blood transfusion generally refers to allogeneic transfusion, which is the safe importation of blood or blood components provided by another person with the same blood type as the recipient. The hazards of blood transfusion are analyzed in terms of non-hemolytic febrile reactions, allergic reactions, and disease transmission. 1. Non-hemolytic febrile reaction: If pyrogen exists in blood products, anti-leukocyte or platelet antibodies may be produced in the patient’s body after transfusion, causing immune reaction and leading to fever, which may be manifested as fever, chills, vomiting and other symptoms in the recipient. 2. Allergic reaction: when the recipient is allergic to the protein substances in the blood, or the input blood carries allergic antibodies, etc., there may be a generalized rash, obvious edema of the larynx, spasm of the bronchial tubes, or even anaphylactic shock in the process of blood transfusion. 3. Disease transmission: If the operation is not done properly, blood transfusion may also infect AIDS, hepatitis B and other diseases through blood transmission, of course, this situation is rare. The harm of blood transfusion is generally very small, as long as strictly grasp the indications for blood transfusion, standardized operation, most of the complications of blood transfusion can be prevented.