It is of great significance for rational, safe, effective and correct use of drugs to correctly judge the validity and expiration period of drugs. For general consumers, only in this way can the quality of drugs be guaranteed.

　　The period of validity:

　　The time limit for ensuring the quality of a drug under certain conditions. Due to the difference of physical and chemical properties and storage conditions of drugs, the validity period is often different, generally speaking, the validity period of drugs is 1-5 years. Drugs that are not prescribed or have an expiration date are usually counted as five years. We can judge whether the drug is expired or not according to the production batch number.

　　The batch number of a domestic drug is usually composed of 6-8 digits, with the first two indicating the year of production, the second two indicating the month of production, and the last two to four indicating the number of batches. For example, the batch number is 110520, indicating that the drug is the 20th batch produced in May 2011. If the validity period is 2 years, the drug can be used until May 31, 2011. If a drug is valid until October 2011, it can be used until October 30, 2011.

　　Expiration date:

　　Refers to the date when the quality of the drug fails to meet the quality standards and requirements recognized by the state and cannot be used again under the stipulated storage conditions. It has two different meanings than the validity period. If the expiration date of a drug is July 2011, the drug may expire on June 30, 2011, and cannot be used again on July 1, 2011. If the expiry date is July 2011, the drug can be used until the last 30 days of July 2011. It can be seen that the expiration date indicates the starting time when a drug cannot be used, while the expiration date indicates the deadline by which a drug can be used. The two are easily confused and should be distinguished.