Adverse drug reactions are harmful reactions unrelated to the purpose of drug use that occur under normal dosage of qualified drugs. It includes the side effects, toxic effects, after-effects, allergic reactions, idiosyncratic reactions, secondary reactions, dependence, teratogenic and carcinogenic, mutagenic effects of drugs, etc. However, adverse drug reactions do not include reactions caused by overdose of drugs, reactions caused by improper use of drugs, and incidents of harm caused to patients by fake and substandard drugs. Adverse drug reactions and drug quality accidents and medical errors, there is a fundamental difference, is strictly distinguished. In our real life, the incidence of adverse drug reactions is quite high, especially in the long-term use or the use of a large amount of drugs, the situation is more serious, and even serious toxic reactions may occur. Strictly speaking, almost all drugs may cause adverse reactions under certain conditions, but as long as the rational use of drugs, you can avoid or minimize the harm. This requires medical workers to have a comprehensive understanding of the pharmacological properties of the drug before use, to strictly grasp the indications of the drug, to choose the appropriate dose and course of treatment, to clarify the contraindications of the drug, and to closely observe the changes in the process of using the drug, and to find the adverse reactions to the drug, should be dealt with in a timely manner. Patients should follow the doctor’s instructions, do not take the medication, I feel that my symptoms have worsened, or symptoms reduced, the dose of drugs to increase or decrease, change the frequency of medication, or think I am better, simply do not eat, try to avoid adverse consequences.