The absorption of oral drugs is mainly influenced by gastrointestinal factors, and taking drugs before or after meals is to make them more effectively absorbed. After the drug enters the gastrointestinal tract through oral intake, it is absorbed into the blood through digestion and then transported to the lesion site through blood circulation to take effect. For oral drugs, the absorption in the gastrointestinal tract is the first and most critical step. Some drugs are easily absorbed in the stomach, while others are absorbed in the small intestine, avoiding the stomach, and the physicochemical properties of each drug are different. Therefore, some drugs need to be taken before meals in order to make them better absorbed into the body and take effect.