Certain drugs are prone to allergic reactions during clinical use, such as penicillin, streptomycin, cytochrome C, etc. Common allergic reactions include rash, urticaria, dermatitis, fever, angioneurotic edema, asthma, anaphylaxis, etc., of which anaphylaxis is the most serious and can even lead to death. In order to prevent the occurrence of allergic reactions, especially serious allergic reactions, it is stipulated that some drugs prone to allergic reactions need to be tested for skin sensitivity before use, and drugs with negative skin tests can be given to patients, while those with positive skin tests are prohibited.