Ascorbic acid was absorbed across the mucosa of the human mouth. 2. Omission of sodium ions from the medium decreased the absorption of ascorbic acid. 3. The presence of D-glucose, or 3-O-methyl-D-glucose, increased the absorption of ascorbic acid but D-fructose had little effect and D-mannitol had no effect. 4. Calcium ions also increased ascorbic acid absorption probably by a secondary effect on "Na+ fluxes. 5. Buccal mucosa was also permeable to dehydroascorbic acid and D-isoascorbic acid.
