Rational drug use, its concept refers to the selection of the best drugs and their preparations according to the type of disease, the patient’s condition and pharmacological theory, the development or adjustment of the drug administration program, effective and safe, economic, appropriate measures to prevent and cure the disease. The rational use of drugs should take into account the following aspects: First, it is the choice of drugs, the use of drugs is directly related to the success or failure of treatment. In the choice of medication, it is necessary to consider whether there is a need to use the drug, and then available can be used when not to use the drug. If it is necessary to use, the drug with the best efficacy is preferred. Also weigh the efficacy of the drug and the severity of adverse drug reactions. Second, is the choice of the preparation, the same drug in the same dose, different preparations will cause different drug effects. Third, the choice of dose, the clinically prescribed common dose generally refers to the average dose of adults, the response to the drug is different from person to person, the dose required by children is smaller, according to age, weight, body surface area according to the adult dose to convert. For the elderly, the dose can be reduced according to the adult dose as appropriate. In addition, for patients with weakness, poor nutrition or hepatic or renal insufficiency, the dose of the drug should be reduced accordingly. Fourth, the choice of route of administration, different routes of administration, the effective concentration of drugs in the body and the efficacy of the close relationship. For example, magnesium sulfate, intravenous administration produces a sedative effect, while the role of oral administration is to guide the drainage, various methods of drug delivery have its characteristics. Clinical mainly according to the patient’s situation and the characteristics of the drug to choose, five, then is the time interval of drug administration, the time of drug administration and the choice of the course of treatment, the appropriate time interval of drug administration, is to maintain the stability of blood concentration, to ensure that the drug is non-toxic and effective necessary conditions. The duration of drug administration should be determined by the specific drug. Drugs that are easily affected by stomach acid should be taken before meals, such as antacids, and drugs that are easily irritating to the gastrointestinal tract should be taken after meals, such as aspirin. Sedative-hypnotic drugs, on the other hand, should be taken before bedtime in order to establish their efficacy and fall asleep at the right time. The length of treatment should depend on the condition, and the medication can usually be stopped when the symptoms disappear. However, patients with chronic diseases that require long-term medication should be given according to a prescribed course of treatment, such as anti-tuberculosis drugs, which should be used continuously for at least six months to more than a year. In addition, the length of treatment should be based on the toxicity of the drug. For example, anti-cancer drugs should be administered using intermittent therapy.