1. Certain sugars were transported across the buccal mucosa by a carrier-mediated mechanism.
2. The metabolic loss of sugars from the mouth in a 5 min test period was negligible.
3. The buccal mucosal transport process was stereospecific for d-glucose and l-arabinose.
4. The absorption of d-glucose, galactose and 3-O-methyl-d-glucose was at least partly dependent on the presence of sodium ions in the luminal fluid.
5. The transport of d-glucose was inhibited by galactose and 3-O-methyl-d-glucose, suggesting at least one common carrier system.