Affections of the major salivary glands are relatively rare in stomatology; but according to the indications of several authors, the proportion of sialolithiasis to the total amount of affections of the salivary glands (ranging from 20.5 to 55.5%) is great. The concretions are, as a rule, located in the duct system of the submandibular gland where they may reach, circumstances permitting, considerable sizes. The author's own investigations evidence that these calculi have a partly regular, partly irregular shell-like structure around a non-calcified centre. Chemical analysis by means of X-ray diffractometry revealed hydroxyapatite varying in the degree of cristallinity as the major component. Precursors in the form of octacalcium phosphate and dicalcium phosphate dihydrate have been disclosed. Salivary calculi must be removed (most frequently by surgical intervention) to avoid secondary diseases of the duct system of the respective gland.