Abstract
Dry mouth, also known as xerostomia, is a condition which occurs when there is a decrease in the amount of saliva, and also the symptom of a dry feeling in the mouth. Saliva has many important functions, therefore a prolonged reduction in the saliva flow amount can have serious consequences to a person's overall health. In Japan, there are 8 million patients suffering from dry eye and it is thought that these patients have the same dry symptoms of their mouth. Also epidemiological data in Western countries state that 25% of the population has various dry mouth symptoms, so from this we can estimate that 30 million patients in Japan may suffer from dry mouth. In this chapter, I will review recent progress in understanding on pathological conditions of dry mouth.
