Three types of sialorrhea can be distinguished: -- deglutition disorders, especially in patients with Parkinson's disease and those with anxiety, -- ptyalomania, -- primary hypersecretion at rest. Functional scintigraphic studies enable a physiological approach to be made, and this tends to group together, under the name of primary hypersecretion at rest, various clinical manifestations occurring in two main groups: -- elderly women complaining of a bitter taste in the mouth, -- plethoric men with large salivary glands. The scintigraphic recording apperances of secretion at rest, which occurs early and without obvious food stimuli, are also noted in other clinical types. It remains to be demonstrated whether they have a common physiopathological basis arising from disorders of the normal sensitivity of the buccal cavity.