Abstract: The study was carried out in a test group of six partially gastrotomized human volunteers by the urinary excretion method and results obtained were compared with a control group of nine healthy human volunteers. Both groups received three riboflavin solid dosage forms with two different dosage regimens in a crossover design. The observed data were fitted to a two compartment model by using the PKP Ⅱ (2) digital computer program on a microcomputer for both dosage regimens for each subject.A significant difference in the amount of excretion of riboflavin was found between the two groups, urinary recovery of riboflavin was lower in the test group than in the control group (P<0.01). In comparing the pharmacokinetic parameters, Ka was significantly greater and Tmax was significantly less in the test group than in the control group, but no statistically significant difference in the values of β was observed.These differences are attributed to gastric emptying rates as well as the dissolution rates of the dosage forms.These results suggest that it is practically possible to increase the bioavailability of persons after partial gastroctomy by administering rapid release preparations or by multiple dosage regimen.