Swollen gums in the back teeth may be caused by gingivitis, periapical periodontitis, oral ulcers and other diseases, need to take medication for the cause of the disease. 1. Gingivitis: swollen gums in the back teeth may be caused by gingivitis. Patients can follow the doctor’s instructions to use antibacterial rinses, such as chlorhexidine. Or cooperate with the doctor to use local hydrogen peroxide solution rinse. 2. Periapical periodontitis: swollen gums of the back teeth may also be caused by periapical periodontitis. Patients can take oral antibiotics under the guidance of the doctor, such as metronidazole, cefuroxime and so on. Or oral pain medication, such as ibuprofen. And cooperate with the doctor for root canal treatment. 3. Oral ulcers: the gums of the back teeth are also considered to be swollen and painful due to oral ulcers. Patients can follow the doctor’s instructions for external pain medication, such as lidocaine gel, or oral vitamin drugs, such as vitamin C, vitamin B and so on. There are many reasons that lead patients to have swollen gums and pain in the back teeth, and it is recommended that patients go to the regular hospital to find out the cause of the disease. Once the diagnosis is confirmed, you need to actively cooperate with the doctor to take relevant treatment measures.