The rate of salivary glucose clearance was determined in 6 subjects after rinsing with solutions ranging in concentration from 0.3 to 50%. 6 repeated rinses of 10% glucose by 1 subject gave clearance times, i.e. time to reach 10 mg%, ranging from 18.7 to 24.6 min, while the clearance time of single rinses by each of the subjects ranged from 13.6 to 23.3 min. The coefficients of variation were 9.8 and 21.7%. Plotting the logarithm of the saliva concentrations of glucose against time gave linear curves (r close to ––1), with slopes which decreased with increase in rinse concentration. The mean half-time, i.e. the time required for a given concentration to reach half its value, was 0.8 min for the 0.3% rinse, increasing to 2.8 min for the 50% rinse. The time of clearance from the initial concentration to a baseline value of 10 mg% increased linearly with the logarithm of the rinse concentrations, and ranged from a mean of 3.2 min for the 0.3% rinse to a mean of 27.5 min for the 50% rinse. There was considerable between-subject variation in the rate of clearance, the rate for a given subject being consistently slow or consistently fast for all rinse concentrations.