Due to the different constitution of each person, some people will have allergic reactions when taking cephalosporin orally. Cephalosporin belongs to the cephalosporin class of antibiotics and has cross-allergic reactions with penicillin antibiotics, so before taking cephalosporin one must determine whether one has a history of allergy to cephalosporins or penicillins, and if one has a history of allergy, one should avoid using it. The common allergic reactions to cephalosporins are chronic allergic reactions, that is, rash, urticaria, erythema and itchy skin symptoms appear 2-5 days after taking the drug, acute allergic reactions are less common, that is, chest tightness and shortness of breath, dyspnea, angioedema, urticaria, and some even transient shock appear soon after using the drug, if these appear, the drug should be stopped immediately and anti-allergic treatment should be carried out. Cephalosporin is commonly used to treat infections of the respiratory tract, urinary tract, and soft tissues of the skin caused by sensitive bacteria. If cephalosporin is allergic, you can choose other classes of antibiotics for treatment, such as macrolide roxithromycin, azithromycin, etc.