Salivary secretions fulfill some specific functions within the human organism, which are explained. The scientific research concerning these fluids dealt during the last years especially with the formation of these secretions within the glands. These investigations have been performed mostly in animal experiments. The results obtained are briefly summarized. For investigations in human salivary secretions, it was necessary to develop some new techniques for collecting the secretions from separate glands. The interpretation of sialo-chemical facts is often difficult as there are many factors, influencing the flow-rate and the composition of the fluids. These factors, as known up to now, are explained. In separate chapters, the inorganic and organic composition of human salivary secretions is described. Concerning the protein-composition of human saliva, there are some newer results as aspects, which are discussed. It must be the aim of a chemical analysis to discover the interrelation between the differences in salivary secretions and pathological conditions. Therefore changes of the salivary secretions in systemic diseases are reported as well as changes in the compositions of these fluids in pathological conditions of the glands themselves. According to the results from own experiments and from the literature, it should be possible in the future, to develop some new diagnostic methods by analysing the salivary secretions.