Penicillin allergy can eat cephalosporin, but need to be alert to the possibility of cephalosporin allergy, need to do skin test before use, penicillin allergy symptoms are serious such as the emergence of shock, laryngeal edema is not recommended to use cephalosporin. Penicillin and cephalosporin are both β-lactam antibiotics, but the structure of cephalosporin is more stable than that of penicillin, so cephalosporin allergy is relatively rare. Even if you are allergic to penicillin, you are not necessarily allergic to cephalosporin. Patients who are allergic to penicillin, but the allergic symptoms are limited to localized rash, can also consider the use of cephalosporin drugs, before the use of cephalosporin drugs need to improve the skin test, such as a negative skin test, then you can use cephalosporin drugs. If the patient is allergic, and serious allergic reactions occurred during the use of penicillin, such as anaphylaxis, laryngeal edema, etc., in this case in order to ensure the safety of the continued use of cephalosporin antibiotics is not recommended. If the use of penicillin is only a mild allergic reaction, cephalosporin can be used if the skin test result is negative.