If the expiration date of the month, if the drug is valid until June 30, 2002, the drug is stored according to the requirements or has not been opened, it can be taken on or before June 30, and it is not recommended to take it again after the expiration date. If the expiration date is only written to the month of the case, the month can be served. Drugs have reached the shelf life, if it has been opened, not in accordance with the requirements of preservation, the role of the drug may be weakened, may have an impact on the therapeutic effect of the disease, is generally not recommended to take, not only can not treat the disease, the human body health is also unfavorable. Almost to the shelf life of the drug, that is still within the period of validity, if the drug is strictly in accordance with the requirements of preservation, the drug has not opened the package, as long as in the provisions of the expiration date, can be used.