Blood transfusion is to input blood into the body through vein, and common complications include: 1, non-hemolytic fever: occurring in the process of blood transfusion or within 1-2 hours after transfusion, manifested as high fever, chills, body temperature up to 39-40 degrees Celsius, accompanied by skin flushing, headache, nausea, vomiting; 2, allergic reaction: most often occurring at the late stage of transfusion or at the beginning of the transfusion, manifested as confined or generalized erythema, edema of the eyelids or lips, and even dyspnea. Even dyspnea, unconsciousness; 3, hemolytic reaction: the most serious, manifested as headache, flushing, chest tightness, numbness of limbs, severe pain in the waist and back, hematuria, drop in blood pressure, which can be combined with acute renal failure, bleeding.