An adverse drug reaction is defined as a harmful reaction unrelated to the purpose for which the drug is administered or unexpected when a qualified drug is used in its normal dosage. Adverse drug reaction is defined as a harmful and undesired reaction not related to the purpose of drug application, which is causally related to the application of the drug and which occurs during normal application of the drug at the prescribed dosage. Common clinical symptoms of adverse drug reactions include nausea, vomiting, skin rash, diarrhea, and other mild discomfort, and patients need to stop taking the drug in time when these symptoms occur. Generally, they can recover on their own. If the symptoms do not improve, it is recommended to go to the hospital for further examination and treatment under the guidance of the doctor. Before taking the drug should carefully read the instructions, for the drug contains ingredients allergic to people, or have special labeling contraindications can not take the drug.