There are the following differences between taking drugs before and after meals. For the irritation of the mucosa of the gastrointestinal tract, drugs taken before meals are usually chosen to have a protective nature for the gastric mucosa. For example, drugs such as proton pump inhibitors and compound thioglycollate, which itself plays a protective effect on the gastric mucosa and at the same time has the effect of inhibiting gastric acid secretion, so taking them before meals will have a protective effect on the gastrointestinal tract. proton pump inhibitors, such as omeprazole, pantoprazole and other drugs can be taken before meals. The drugs eaten after meals are usually drugs that have some irritation for the gastrointestinal tract, such as antibiotics, non-steroidal anti-inflammatory drugs, etc., usually cephalosporins, azithromycin, ofloxacin, roxithromycin, ibuprofen, etc., which can cause some irritation to the mucous membrane of the gastrointestinal tract, so they are taken after meals.