The pharmacokineties of mannitol and glycerol was studied in rabbits and 5 volunteers. Mannitol and glycerol concentrations in serum were measured by using spectrophotometric method. The serum concentration-time profiles of mannitol after iv administration of 1 and 2g/kg in rabbits and iv infusion of 50g in humans showed an open two compartment model with the following equations:Ct=3644e-2.40t+5092e-1.01t for rabbits after iv 1g/kg

C

=4698e-1.t+11464e-0.70t for rabbits after iv 2g/kg

andC

=l337e-10.20t + 3962e-0.36t for humans after iv infusion of 50g.The profiles of glycerol after iv administration of 0.5 g/kg in rabbits showed an open one compartment model with the equation: C

= 2670e-1.64t.The values of elimination half life (t(1/2) Ke) of mannitol in rabbits (1 and 2g/kg) and inhumans were 1.C4±9.43

1.10 ± 0.20 and 1.91 ± 0.12h respectively. The values of t

Ke obtai-ned from two doses of mannitol in rabbits were found to be of ao significant difference (p> 0.06). The results of apparent volume of distribution (Yd

ml/kg) for mannitol in rabbits (1 and 2g/kg) and in humans were 227±77

173±33 and 209±21 ml/kg respectively. Whereas the Vd of glycerol in rabbits experiment was 193±56ml/kg. There was no significant difference (p>0.05) in the results of Vd of mannitol and glycerol for both rabbits and human studies