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 diets are hard to sustain for the long term. One specific liquid diet doesn't exist. Many variations of a very-low-calorie diet that has you subsist on juice, clinically prepared nutritional drinks, smoothies, or concoctions of cayenne pepper and lemon juice for days, weeks or even months persist, however.