There are many causes of dry mouth. Dry mouth most commonly occurs as a side effect of medications that cause decreased saliva production, including high blood pressure medications, antihistamines, antidepressants, diuretics, nonsteroidal anti-inflammatories, narcotics, and many others.
Liquid diet: The Liquid diet is the restriction of solid food intake, and replacement of solid food with liquids. In hospitals, liquid diets are prescribed by doctors for a number of reasons for patients who are unable to consume solid foods. Liquid diets may be prescribed following surgery or as a preparation for certain medical procedures.
Liquid and soft diets are recommended in many situations, including some types of dysphagia (difficulty swallowing), surgery involving the mouth or gastrointestinal tract, and pain from newly adjusted braces. Liquid diets contain no solid foods. A Clear Liquid Diet consists of transparent liquids and no opaque liquids or smoothed solids. (e.g. meat or vegetable broth, bouillon, clear fruit juices, clear fruit ices, popsicles, clear gelatin desserts, clear carbonated drinks, hard candies, and black tea or coffee)