The first swelling and inflammation of root canal treatment may require open drainage, anti-inflammatory medication, or extraction of the affected tooth. It is recommended to go to the hospital for radiographic examination and prompt treatment. Root canals do not remove the residue in the tooth thoroughly enough, and the rinsing pressure flushes the infected material out of the apical foramen during the treatment process may cause apical swelling; a tooth with a fragile root may undergo a splitting manifestation during the root canal treatment, which leads to swelling of the tooth. Infected swelling can be treated by removing the temporary seal, flushing the root canal, adequate drainage, and if necessary, incision of the swollen gums for drainage. Swelling can be treated with anti-inflammatory drugs as prescribed by the doctor, such as: erythromycin plus metronidazole, amoxicillin plus metronidazole. If the diagnosis of tooth splitting is confirmed by radiography, the tooth can be extracted and treated.