For periapical pain taking drugs, first need to understand the patient’s drug allergy history, such as penicillin, cephalosporin, and other antibiotics, as well as the history of alcohol consumption, if none of them, periapical pain drugs will mostly choose cephalosporin or penicillin-based antibiotics, such as amoxicillin oral. In addition, a nitrazole class of drugs, such as metronidazole, tinidazole, ornidazole, should be added. This is because cephalosporin and penicillin are broad-spectrum antibacterial drugs, while metronidazole, tinidazole, and ornidazole are anti-anaerobic drugs. The flora that cause periapical periodontitis include not only Staphylococcus aureus and other bacteria, but also anaerobic bacteria, so a combination of both drugs is needed to solve the problem.