Abstract: The basic clinical pharmacokinetics and oral bioavailability of three different pharmaceutical preparations Of Sodium Phenytoin have been studied in 6 normal volunteers. Plasma concentrations of the drug were determined by using high-pressure liquid chromatography following oral administration of 200mg of Sodium Phenytoin. The mean time and height of the peak plasma level and absorption rate constant of phenytoin were the same in both sugar-coated tablets and ordinary tablets. However, the mean plasma half life of elimination (t 1/2β) of Phenytoin in sugarcoated tablets was longer than that in ordinary tablets. The average oral bioavailability of Phenytoin in ordinary tablets and in sugar-coated tablets was 74.71% (n=6) and 89.76%(n=6), respectively.