Due to the different physical constitution of individuals, some patients may experience allergic reactions after taking cephalosporin, and whether they can disappear on their own should be decided on a case-by-case basis. Cephalosporin is a widely used antibiotic with bactericidal effect, but some patients may have allergic reactions, with rash, urticaria and erythema more common. If the symptoms are mild, they can recover on their own by stopping the medication and drinking an appropriate amount of water to promote the metabolism of the allergenic drug. If the allergy is severe, resulting in a drop in blood pressure, shortness of breath, wheezing and difficulty in breathing, it cannot recover on its own and requires immediate resuscitation and, if necessary, treatment with a ventilator. Patients should do drug allergy test before using cephalosporin, and those who are tested to be allergic to cephalosporins or have a history of allergy are prohibited. Once an allergic reaction occurs, discontinue use immediately, keep the respiratory tract open, and follow medical advice on medication according to specific symptoms.