Toothache after taking metronidazole more pain may be improper treatment, mostly considered to be caries, endodontitis, apical periodontitis and other diseases caused by the cause of the need to take medication, surgical treatment, other treatments, etc., the use of metronidazole in these cases has no significant therapeutic effect. 1. caries: for caries, no need to use metronidazole, toothache can be prescribed to use ibuprofen, acetaminophen and other non-steroidal anti-inflammatory painkillers. Normally, fluoride such as 8% stannous fluoride solution or 75% sodium fluoride glycerin paste should be used as prescribed by the doctor, and fissure sealing treatment or remineralization therapy should be carried out in the early stage. If the tooth body tissue is damaged, it is necessary to take filling and restoration. 2. Pulpitis: this disease does not need to take metronidazole, for acute pulpitis need to be taken to open the pulp drainage surgery to reduce pain, if to save the pulp for the purpose of treatment, need to be taken to direct pulp capping, pulp cutting; if to save the affected tooth for the purpose of treatment, need to be carried out root canal treatment. 3. Periapical periodontitis: This disease usually requires the combined use of antibiotics such as metronidazole and ceftriaxone as well as painkillers such as ibuprofen as prescribed by the doctor, so the use of metronidazole alone is not effective in relieving pain. Endodontics is required at the end of the acute phase, or microscopic apical surgery if the results are poor. It is recommended that patients with toothache who have more pain after taking metronidazole go to the hospital, cooperate with the doctor to actively treat the primary disease, the use of drugs need to follow the doctor’s instructions.