Saliva is critical in maintaining oral health and comfort. Our laboratory has investigated several disorders of salivary glands. The purpose of this protocol is to obtain data from healthy volunteers for comparison with data from patients with salivary dysfunction. We plan to utilize the NIH Clinical Center Clinical Research Volunteer Program to solicit paid participation from healthy adults. Study procedures are accomplished in 2-3 outpatient visits that include an interview, saliva collection, lip biopsy, clinical laboratory studies, dry eye examination, and lip biopsy follow up, as needed. These are routine diagnostic procedures. Biopsy specimens may be used in clinical and laboratory studies, such as in vitro biochemical analysis or in vivo transplantation.