Dry mouth may be due to the body’s adverse reaction of mild fever after receiving the new crown vaccine, which leads to an increase in body temperature and then self-consciousness of dry mouth. Part of the population may have an adverse reaction such as low fever after receiving the new crown vaccine, which in turn causes dry mouth and other symptoms, and can usually be relieved on its own in 2~3 days. Dry mouth usually does not have a greater impact on the body, timely hydration can effectively relieve the symptoms of dry mouth. In addition, it cannot be ruled out that it is caused by external factors. If the ambient temperature is high when the new crown vaccine is administered, or if there is a high salt food intake before the new crown vaccine is administered, the symptoms of dry mouth may also occur, and it is recommended to supplement enough water to alleviate the symptoms at this time. After vaccination, it is recommended to eat a light diet, consume more vegetables and fruits rich in vitamins and sufficient water, drink plenty of water, and pay attention to rest, which is beneficial to alleviate the adverse reactions after vaccination.