Gums hurt when eating hot and cold things may be dentin allergy, periodontitis, pulpitis, deep caries caused by pain, should be dealt with promptly. 1. Dentin allergy: teeth in the external stimuli can lead to symptoms of pain, the onset of symptoms quickly, sharp pain, short time. Dentin tubules need to be closed to reduce or avoid the flow of fluids within the dentin. 2. Periodontitis: with the increase of age, the prevalence of periodontitis will gradually increase, the early stage is red, swollen gums, bleeding with bad breath, with the spread of inflammation will appear periodontal abscess, loose teeth and other symptoms, eating hot and cold things are painful, need to remove tartar, under the guidance of the physician to take anti-inflammatory drugs to eliminate the gums gingivitis treatment, serious cases require surgical treatment. 3. Pulpitis: pulpitis is an inflammatory lesion of the pulp tissue, manifested by teeth eating hot and cold, sweet and sour food will appear pain, acute pulpitis will appear toothache, night pain, pain can not bear, the fastest way to relieve is to go to the hospital to open the pulp drainage, root canal treatment, and take anti-inflammatory medication under the guidance of the doctor, the need to pay attention to the dietary adjustments. 4. Deep caries: If the caries is deep, eating hot and cold things will stimulate the nerve and cause pain. Patients need to undergo root canal treatment to remove the caries and fill the tooth. Gums eat hot and cold things are painful need to consult a doctor in time to identify the cause, for the cause of treatment.