No matter what kind of drugs, once the expiration date is expired, they can not be used again, including Cefadroxil tablets. 1. After the shelf life of the drug, not only can’t play the proper effect, but also will not have any effect due to the reduction of the active ingredients of the drug, or even drug denaturation, which will lead to a lot of serious adverse consequences, such as liver and kidney damage, allergic reactions and so on. 2. Cefadroxil is an antibiotic drug, its main function is to resist bacterial infection, after the shelf life, not only can not control the infection, but also may cause the spread of inflammation, sepsis and so on. Therefore, do not take the drug after the shelf life, if accidentally taken and symptoms should be timely medical treatment to avoid adverse consequences.