Toothache when eating cold things may be caused by pulpitis, dental caries or pulp allergy, it is recommended to identify the cause of the disease and carry out targeted treatment. 1. Pulpitis: If the tooth hurts when eating hot food in addition to eating cold things, there will also be pain when eating hot food, and there will be pain when doing chewing movements. Root canal treatment should be carried out to close the root canal of the tooth and then repair the tooth. 2. Dental caries: Filling treatment can be carried out, grinding away the decayed dentin, and then filling the cavity with composite resin to avoid further development of caries to the depth and destruction of the nerve. 3. Dental pulp allergy: due to long-term eating hard food, such as dried fruits or gnawing on bones, etc., it will wear down the teeth and jaws, and grind the dentin thinner and thinner, which may expose the nerves of the teeth, so it is recommended to use anti-allergy toothpaste and pay attention to dietary choices. You can also seek desensitization treatment to cover the exposed dentin.