Contrast media used for sialography were originally developed for other medical applications. Therefore, it was considered desirable to investigate the properties of these substances for use in sialography. Eleven radiopaque substances were selected, and their properties for sialography were studied. An in vitro study was made to determine their contrast qualities and their rate of evacuation after the sialographic examination. In animal experiments the possible harmful effects of the media on salivary gland tissues were studied. Moreover, the effects of the radiopaque material on the extraglandular tissues--which are important in understanding the consequences of spilling into these tissues--were investigated. The results of this study were compared with data from the literature. Conray 80, Amipaque 440, Lipiodol UF, Myodil, and Duroliopaque appear to be the media most suited for sialography, provided glandular overfilling is avoided. A prolonged clinical study is advised for a further selection from these agents.