There is no herbal medicine for dry mouth at night. If you drink normal water, dry mouth at night may be caused by a deficiency of yin in the liver and kidneys or a deficiency of yin and internal heat. The human body contains both yin and yang qi, and the main function of yin qi, in addition to nourishing and nourishing the internal organs and tissues, is also responsible for restraining yang qi, so as not to expose the yang qi. Yang qi is characterized by heat, movement and rising, while yin is characterized by cold, static and falling. Yang qi is dominant during the day and yin qi is dominant at night. So when the organism is deficient in yin and the yin does not control the yang then it will lead to the inflammation of the deficiency fire, burning the fluid, and the lack of fluid cannot moisturize the mouth so it leads to dry mouth. If the patient has dry mouth at night, it may be caused by yin deficiency in the liver and kidney or yin deficiency and internal heat, and Zhi Bai Di Huang Wan can be taken to nourish the yin and reduce the fire, and the contraindications and adverse effects of this drug are not clear. If you are not feeling well, please go to a regular hospital for treatment and use the medication under the guidance of a doctor, so as not to use improper medication and delay the condition.