The comparative steady-state bioavailability of asiatic acid was studied in 12 healthy male and female volunteers following oral administration of approximately equimolar doses of either asiatic acid (12 mg) or the glycoside derivative of asiatic acid, asiaticoside (24 mg). Both asiatic acid and asiaticoside are constituents of the marketed dermatological product Madecassol. Asiaticoside is converted in vivo to asiatic acid by hydrolytic cleavage of the sugar moiety. Steady-state AUC0-12h values for asiatic acid on either regimen were similar (614 +/- 250 ng.h/ml following asiatic acid compared to 606 +/- 316 ng.h/ml following asiaticoside) indicating comparable bioavailability for asiatic acid with the two ingredients at approximately equimolar doses. Since asiatic acid is considered to be the most therapeutically active ingredient of Madecassol, the current data suggest that the therapeutic effects of asiaticoside may be mediated through conversion to asiatic acid.