The aim of the present study was to evaluate the bioavailability of a new tablet formulation of carbocysteine relative against two other oral carbocysteine containing dosage forms, viz. a syrup and capsules. Plasma levels and urine concentrations of carbocysteine were monitored, following oral administration of all three dosage forms to healthy human volunteers, by direct derivatization of carbocysteine using dabsylchloride and subsequent high performance liquid chromatography. There was no difference in bioavailability of carbocysteine from these dosage forms as expressed by the respective areas under the plasma concentration-time curves and total amounts of unchanged carbocysteine excreted in urine.