When is it more appropriate to take aspirin? First, take it before or after meals? This is mainly due to the damage of aspirin to the stomach. The mechanism of aspirin induced gastrointestinal bleeding mainly has two points: 1, the direct damage of aspirin to the mucosa of the gastrointestinal tract; 2, aspirin inhibits the activity of cyclooxygenase (COX), reduces the synthesis of prostaglandin (PG), the protective factor of gastrointestinal mucosa, reduces the synthesis of thromboxane A2 (TXA2), reduces the aggregation ability of platelets, and easily causes bleeding. At present, it is rarely used as a general preparation, and if it is a general preparation it should still be taken after meals, so that aspirin is mixed with food, which can reduce the direct damage to the gastric mucosa. However, the vast majority of those currently used to prevent cardiovascular events are enteric-coated tablets. Enteric tablets have an acid-resistant but not alkali-resistant envelope outside, and are generally released only in the alkaline environment of the intestine, which can reduce the direct stimulation of the stomach, but they are not released without decomposition in the stomach, according to the pharmacopoeia, the amount released in the stomach is less than 10%, which means that a small amount is still released in the stomach. If taken after a meal, the food will dilute the stomach acid after eating, resulting in a higher pH in the stomach, which is closer to an alkaline environment, thus speeding up the decomposition of the drug in the stomach. In addition, if taken after a meal, the drug is mixed with food, which delays its emptying time and stays in the stomach longer and releases a little more. When taken before a meal, because of the strong acidic environment in the stomach on an empty stomach, the enteric coating is not easily dissolved and the stomach empties quickly, resulting in a shorter stay in the stomach, thus reducing the damage of the drug to the gastric mucosa. Therefore, according to the above-mentioned basis and the requirements on the drug instructions, it is best to take aspirin enteric-coated tablets before meals. For patients with combined gastrointestinal side effects, gastric mucosal protectors or proton pump inhibitors can be used in combination. Second, is it better to take it in the morning or in the evening? In my clinical work, I often have patients ask: “Is it better to take aspirin in the morning or in the evening? “In fact, the Chinese Expert Consensus on the Clinical Application of Aspirin and several other expert consensuses on hypertension and coronary heart disease do not make provisions for this issue. Some scholars prefer to take it at night. The reason is that the high incidence of cardiovascular events is from 06:00 to 12:00, and the peak blood concentration of aspirin can only be reached 3-4 hours after taking the drug, so if the product is taken every morning after waking up, it will not have the best protective effect. 18:00 to 24:00 is the active time of human platelet production, so taking aspirin at night can make its effect more time-efficient. Some scholars also prefer those who take it in the morning. Prostacyclin has vasodilatory and anti-platelet aggregation effects. Prostacyclin levels in the blood are higher at night than during the day when aspirin is taken in the morning. In contrast, when aspirin is taken at night, the prostacyclin in the blood is higher during the day than at night. The body’s clotting level is highest at night, so taking aspirin in the morning is more effective for vasodilation and anti-platelet aggregation disorders. In fact, each has its own reasons for whether to take it in the morning or at night. The current expert opinion is that the effects of long-term aspirin use are continuous and that morning and evening make little difference, the key is persistence! All patients who meet the indications for taking aspirin and who do not have side effects such as gastrointestinal bleeding or asthma attacks while taking it, need to need to take it for a long time as long as they can tolerate it.