Penicillin allergy does not always cause death, but if symptoms are severe and not treated promptly, death is likely to occur within minutes to hours. Penicillin allergy will result in itchy skin, rash, angioedema, allergic rhinitis, asthma, dyspnea, nausea, vomiting, and laryngeal edema, among which anaphylaxis is the most serious, with a morbidity and mortality rate of 10%-20%. If the symptoms of allergic reactions are mild, after timely anti-allergic and symptomatic treatment, they will generally be relieved soon and will not affect life. If anaphylaxis occurs and treatment is not timely, death may often occur within minutes to hours. Some of them may be temporarily relieved by resuscitation, but due to insufficient blood perfusion to major organs caused by shock, death may still occur during subsequent treatment, and its specific time cannot be determined. Before applying penicillin clinically, an allergy test must be done. Even if the previous penicillin skin test is negative, a skin test is still required when penicillin is applied again and should not be taken lightly.