Healthcare providers do not always recognize dry mouth and the problems associated with it. The symptoms of dry mouth and the patterns of complaints associated with it are the feeling that the mouth is dry; foamy or very watery saliva; a red appearance of the mucosa under a denture and the excessive presence of remaining food particles on the mucosa or the denture. The most serious detrimental aspect of dry mouth complaints is a reduced secretion of saliva, but a feeling of a dry mouth can also exist without an objectively assessed hyposalivation. The most important causes of dry mouth are the side effects of medications, systemic diseases, radiotherapy in the head and neck region and occasionally a psychiatric disorder. Early recognition of the symptoms and the establishment of a precise diagnosis are essential for proper treatment and for optimizing the quality of life of the patient. Basic investigation consists of an extensive patient history, inspection of the head and neck region and the oral cavity, evaluation of the functioning of the salivary glands, and, if necessary, additional investigations.