The nutritional requirements of some strains referred to Scardovia inopinata and Parascardovia denticolens, two new species of the family Bifidobacteriaceae isolated from human dental caries, were studied. The simultaneous, or one at a time addition of pancreatin and pantethine to Gyllenberg's synthetic medium, lightly stimulated the growth, whereas the simultaneous presence of pancreatin, pantethine and inactivated lysozyme to the medium, appeared to be essential for the optimal growth of all the strains examined. A comparison with the species Bifidobacterium dentium, isolated from human dental caries as well, was carried out.