The left side of the face suddenly swollen, common causes are as follows: First, the patient in strenuous exercise when a sudden fall can cause the left side of the face swelling, accompanied only by skin, subcutaneous soft tissue injury can be given as soon as possible to ice compresses, to reduce tissue exudate to promote the absorption of local inflammation can be faster to relieve the swelling of the face; patients accompanied by local fracture when the application of drugs is not able to reduce the swelling, the patient needs to go to the hospital as soon as possible to complete the CT scan to clarify the exact cause of injury Second, the patient’s left side of the tooth ulceration, tooth extraction will also appear after the left side of the face swelling, dental trauma will also be accompanied by blood seepage and infection need to be given to the hemostatic cotton wool ball pressure to stop bleeding, oral anti-inflammatory drugs, do not eat two hours after the extraction of teeth to avoid bleeding aggravation, two to three days after the oral inflammation and hemorrhage control, swelling can be self-subsorbed.