The common clinical causes of mouth swelling are mainly the following: a. Patients with huge oral ulcers as well as septic infection of the teeth can cause swelling of the lips due to infection of the mouth. At this time, patients can take watermelon cream tablets, metronidazole tablets by mouth and gargle with light salt water to control the oral infection and promote the healing of the ulcer wound. If necessary, the abscessed teeth need to be extracted, and the swelling of the lips can gradually subside after the inflammation is controlled; second, allergic patients will have an allergic reaction after eating mango, tomato, seafood and other allergy-prone foods, which will manifest as obvious swelling of the lips. To reduce the allergic allergic reaction in the body and promote the swelling of the lips to subside faster.