BACKGROUND: In the anesthetic state, various anesthetic agents may effect on hyperosmolar blood-brain barrier disruption. Therefore, the effects of intravenous anesthetics, pentobarbital, ketamine and propofol, on the mannitol induced blood brain barrier disruption (BBBD) of 21 Spague-Dawly rats were evaluated. METHODS: Intravenous anesthetics, pentobarbital (group 1), propofol (group 2) and ketamine (group 3), were administrated before right intracarotid artery infusion of mannitol in three groups. BBBD was estimated by the calculation of the ratio of radioactivity between plasma and brain tissue using 99MTC-human serum albumin and Evans blue staining in cerebral hemisphere. Also cerebral blood flow (CBF) was monitored with laser doppler flowmetry. RESULTS: Percent albuminal space of right and left cerebral hemisphere was showed 9.01 +/- 3.47%, 1.65 +/- 1.25% in group 1, 8.02 +/- 2.19%, 1.61 +/- 1.06% in group 2 and 5.63 +/- 1.79%, 1.10 +/- 0.94% in group 3 respectively. Evans blue dye staining was showed 2+~3+ in the right and 0 in the left cerebral hemisphere in all groups. Right cerebral hemisphere showed significantly more blood brain barrier disruption than left cerebral hemisphere in all groups (p<0.01). And there was no significant difference in BBBD among three groups. However, the degree of BBBD of group 3 was drop down to nearly 70-80% of group 1 and 2. The CBF of group 3 was significantly higher than that of group 1 and group 2 after intracarotid infusion of mannitol (p<0.05). CONCLUSIONS: The results suggest that pentobarbital, propofol and ketamine could be used to be anesthetics for BBBD in rats, but some caution should be paid to use ketamine in mannitol induced BBBD.