Metronidazole and oxalic acid detoxification tablets can be taken together and have a certain auxiliary therapeutic effect on periodontitis and apical periodontitis, as follows. 1. Metronidazole: the main component is metronidazole, which has a strong killing effect on anaerobic bacteria, and is clinically used to treat various infections caused by anaerobic bacteria, such as periodontitis and apical periodontitis. Common adverse reactions are gastrointestinal reactions, such as nausea, vomiting and so on. It is prohibited for those with active central nervous system disorders and blood diseases. 2. Niu Huang Antidote Tablets: the main ingredients are artificial niu huang, andrographis, rhubarb, huang cen, etc. It is suitable for symptoms such as sore throat, swollen gums and so on. Common adverse reactions include diarrhea, abdominal pain, rash, chest tightness and so on. It is contraindicated for pregnant women, lactating women, infants and allergic persons. All of the above medicines should be used under the guidance of a doctor, and it is recommended to visit a hospital for regular treatment.