Cephalosporins are a class of antibiotics that may be allergic when applied intravenously in the clinic. Symptoms of allergy may be mild, with only itching and rash on the skin, and can be well controlled by applying an anti-allergic drug, such as promethazine hydrochloride, intramuscularly and with dexamethasone for sedation. However, before applying the medication, the intravenous access to which the cephalosporin is applied should be preserved, and can be replaced with a bottle of saline, or if there is no intravenous access, it should be established as soon as possible. If the cephalosporin allergy, which is very severe, for example, there is significant chest tightness, panic, as well as sweating, consciousness may disappear quickly, there is also a possibility of shock, a drop in blood pressure in this case, it is necessary to promptly apply epinephrine to regulate hemodynamics.