Metronidazole is effective in the treatment of periapical infections, but it is not a complete cure. Metronidazole is mainly used to treat anaerobic infections and eliminate inflammation, but the first choice of treatment for periapical infections is not medication, so the use of metronidazole can only play a supplementary therapeutic role. The preferred treatment for periapical infections is root canal therapy, which first opens the pulp and drains the infected material around the root canal, and then combines the use of anti-inflammatory medications to avoid recurrence of the infection and promote local healing. If apical periodontitis is treated in a timely manner, the affected tooth and its chewing function can be preserved. If it is not treated in time, the infection spreads and may affect the alveolar bone and gum tissues, and the infection recurs, forming refractory apical periodontitis. If medication is needed, it should be prescribed by a doctor.