One side of the tonsil edema slight pain may be tonsillitis, tonsil peritonsillar abscess, tonsil tumor and other causes, need to be based on the specific diagnosis of the disease for treatment, such as taking antibiotic drugs, incision and drainage, tumor resection and other methods of treatment. 1. Tonsillitis: when tonsil inflammation occurs, it will lead to blockage of the upper crypt of tonsil, so that the secretion can not be discharged from the body, which will cause one side of the tonsil edema and slight pain. Antibiotics such as cefixime capsules and amoxicillin capsules can be taken under medical supervision. 2. Peritonsillar abscess: because the inflammation penetrates the tonsil peritonsillar membrane and enters the peritonsillar space, resulting in peritonsillar abscess, which can be manifested as edema of one side of the tonsil with slight pain and difficulty in swallowing. Generally, the pus can be discharged through incision and drainage to achieve the effect of treatment. 3. Tonsil tumor: tonsil tumor can also cause one side of tonsil edema, and develop rapidly, accompanied by painful symptoms. When this disease occurs, it is necessary to cooperate with the doctor to adopt the appropriate plan for treatment after tumor resection. Patients with the symptoms of one side of the tonsil edema mild pain, should go to the hospital in time to receive examination, cooperate with the doctor active treatment. The above drugs need to be used under the guidance of a doctor.