Teeth hurt when drinking hot water is mainly caused by deep caries, pulpitis or acute gingival papillitis, must continue caries filling, root canal treatment or periodontal treatment. 1. Deep caries: Deep caries will lead to loss of hard tissues (e.g. enamel, dentin), which will deprive the pulp of its protection; this will lead to sensitivity to hot and cold stimuli, i.e. pain when drinking hot water; caries filling and restoration is required to prevent the appearance of the above symptoms. 2. Pulpitis: Infected and inflamed pulp tissue can also cause pain from hot and cold stimuli, i.e. drinking hot water can cause toothache; root canal treatment is required to remove the infected and inflamed nerve in order to effectively stop the pain. 3. Acute gingival papillitis: the gingival papillae at the interspace of the teeth due to mechanical or chemical stimulation will appear swollen gums, and will appear similar to the symptoms of endodontitis, hot and cold pain or spontaneous pain; must remove the external stimulus, and the gingival papillae for rinsing and medication in order to alleviate the pain. Teeth are very painful when drinking hot water, it is recommended to consult a doctor for a clear diagnosis and symptomatic treatment in order to avoid delays in the condition.