It is known that the physiological activities of the human body have a time pattern, which is often referred to as the biological clock. Similarly, the absorption, distribution, metabolism and excretion of drugs in the human body also follow this biological time law, which is often referred to in recent years as the “hour of pharmacology”. Commonly speaking, if you can choose the appropriate time to use drugs, will achieve better therapeutic effects. Examples are as follows: painkillers: 11 to 12 a.m., the body’s most sensitive to pain, so painkillers should be taken before this time, that is, 10 a.m. or before lunch. Antiasthmatic drugs: due to the lowering of lung function at night, asthma attacks at night, so anti-asthmatic drugs should be taken before going to sleep. Coronary heart disease treatment drugs: angina pectoris and myocardial infarction and other coronary heart disease in the morning 6 to 12 hours attack, therefore, the treatment of such diseases in the early morning or the morning use of drugs in order to receive the desired effect. Antihypertensive drugs: the human body’s blood pressure in the morning and afternoon each day, there is a natural increase, if the two peaks before, that is, 8 ~ 9 am, 2-3 pm to take antihypertensive drugs, you will achieve the desired results. Ulcer disease treatment drugs: in addition to the daytime, stomach acid still has a secretion peak at night, therefore, in addition to the regular medication during the day, should be added to the anti-ulcer disease drugs once before bedtime. Hypoglycemic drugs: blood sugar tends to rise after meals, so taking hypoglycemic drugs 10 to 30 minutes before meals can prevent the sudden rise of blood sugar after meals. Digestive aids: taking digestive aids before meals can promote the secretion of digestive juices, which is conducive to the digestion and absorption of food. At the same time, the medication should be taken on time. The meaning of on time here is threefold: first, the number of times. Many people have a misunderstanding of twice a day (bid) and three times a day (TId), thinking that it only refers to the 12 hours of the day; in fact, it should be the whole day 24 hours. Twice a day should be every 12 hours, while three times a day should be every 8 hours, so as to maintain an effective and balanced drug concentration in the blood. If the drug is administered three times during the 12 hours of the day, the concentration of the drug in the blood will be too high during the day and too low at night, thus reducing the effectiveness of the drug; secondly, the duration of the drug. Some drugs must reach the prescribed course of treatment to produce results, for example, urinary tract infections must be 7 to 10 days of continuous medication can be cured, if the drug is stopped, will be abandoned; Third, before or after meals. Some drugs are fat-soluble or stimulating effect on the gastric mucosa, must be taken after meals, for example, commonly used aspirin if taken on an empty stomach, may lead to gastric hemorrhage; and some are to protect the gastric mucosa from the stimulation of the regiment or conducive to the absorption of the meal must be taken before meals; for example, bismuth potassium citrate treatment of gastric ulcers should be taken before meals. The above points should be emphasized not only in relation to the effect of the drug, but also in relation to one’s own safety.