Toothache is usually caused by pulpitis or periapical inflammation, drug treatment can only control the development of inflammation, reduce clinical symptoms, and can not eliminate the disease, the tooth will continue to feel pain. 1. Artificial oxalic acid metronidazole is a compound preparation, whose main components are metronidazole and artificial oxalic acid, which has a strong killing effect on anaerobic bacteria, and has a certain therapeutic effect on endodontitis or apical periodontitis caused by anaerobic bacteria. 2. However, the drug is unable to remove the inflammatory tissues in the root canal and periapical area, and the exuded tissue fluid and inflammatory factors will still cause tooth pain. If the tooth pain is severe, or other symptoms appear, it is recommended to go to the hospital in time, with the help of the doctor to carry out targeted treatment, such as pulpitis, periapical periodontitis need to carry out a thorough root canal treatment.