The swollen flesh behind the gums of the back teeth is considered to be caused by wisdom teeth pericoronitis, gingivitis and other diseases, to clarify the cause of the disease, choose the appropriate treatment, such as general treatment, medication and so on. 1. Wisdom tooth pericoronitis: If the swelling behind the gums of the back teeth is caused by wisdom tooth pericoronitis, if the symptoms are mild, you can rinse your mouth with warm salt water, and the situation can be improved. If the symptoms are more serious, it is necessary to seek medical treatment, local rinsing medicine, follow the doctor’s instructions with compound chlorhexidine gargle, polyvidone iodine gargle rinse, with taking metronidazole or injection clindamycin treatment. 2. Gingivitis: For patients with gingivitis, the first thing to do is to remove the local irritants, such as dental scaling to remove plaque, tartar, etc., rinse with hydrogen peroxide solution, and if necessary, can be used with antibacterial gargle gargle, such as Chlorhexidine solution. Patients should go to the local regular hospital, relevant examination, choose the appropriate way to deal with.