The expiration date of a drug is the period during which the drug can maintain its quality under the specified storage conditions. China’s drug control law provides that drugs that are not marked or changed expiration date and drugs that exceed the expiration date are punished as bad drugs. After the expiration date of the drug, it should be regarded as bad medicine, not only is the efficacy of the drug reduced, some drugs will also appear to increase toxicity, so it is not suitable for use. Medicine is a special product that has a corresponding shelf life under certain conditions (such as temperature, humidity, light), and vials should be kept in strict accordance with the storage conditions and used up as much as possible within the expiration date, and the appearance of the medicine should be checked frequently for any abnormalities. The efficacy of the drug will decrease with the prolongation of storage time, and the efficacy of the drug will be reduced to a certain extent, which is considered to be invalid. If the expiration date is exceeded, the expected therapeutic effect will not be achieved and the condition may be delayed after consumption. After the expiration date of the drug, may be due to decomposition, oxidation and other chemical changes and generate some decomposition products, some decomposition products may have adverse effects on the body or even toxic effects. The expiration date is legally significant. Under the specified storage conditions, the drug manufacturer assumes drug quality assurance for drugs within the expiration date. The use of expired drugs, drug manufacturers no longer assume the quality assurance of drugs.