By using two structurally unrelated hydrogen sulfide (H 2 S) donors 5-(4-methoxyphenyl) -3H-1, 2-dithiole-3-thione (ADT) and sodium hydrosulfide (NaHS), this study investigated if H 2 S protected blood-brain barrier (BBB) integrity following middle cerebral artery occlusion (MCAO). ICR mice underwent MCAO and received H 2 S donors at 3 h after reperfusion. Infarction, neurological scores, brain edema, Evans blue (EB) extravasation, and tight junction protein expression were examined at 48 h after MCAO. We also investigated if ADT protected BBB integrity by suppressing post-ischemic inflammation-induced Matrix Metalloproteimase-9 (MMP9) and Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX). ADT increased blood H 2 S concentrations, decreased infarction, and improved neurological deficits. Particularly, ADT reduced EB extravasation, brain edema and preserved expression of tight junction proteins in the ischemic brain. NaHS also increased blood H 2 S levels and reduced EB extravasation following MCAO. Moreover, ADT inhibited expression of proinflammatory markers induced Nitric Oxide Synthase (iNOS) and IL-1b while enhanced expression of anti-inflammatory markers arginase 1 and IL-10 in the ischemic brain. Accordingly, ADT attenuated ischemia-induced expression and activity of MMP9. Moreover, ADT reduced NOX-4 mRNA expression, NOX activity, and inhibited nuclear translocation of Nuclear Factor Kappa-B (NF-jB) in the ischemic brain. In conclusion, H 2 S donors protected BBB integrity following experimental stroke possibly by acting through NF-jB inhibition to suppress neuroinflammation induction of MMP9 and NOX4-derived free radicals. Keywords: Blood-brain barrier, cerebral ischemia, hydrogen sulfide, vasoprotection. J. Neurochem. (2014) 129, 827-838.Disruption of blood-brain barrier (BBB) is a hallmark of stroke pathogenesis, which contributes significantly to ischemic brain damage (Hacke et al. 1996). Clinically, BBB disruption occurs in more than one third of stroke patients and is associated with poor outcomes and lower survival rates following stroke (Warach and Latour 2004). Although experimental stroke has revealed several molecular cascades that contribute to post-stroke BBB disruption, BBB disruption is still inaccessible to therapeutic interventions so far (Rosenberg 2012).Hydrogen sulfide (H 2 S), classically viewed as a poisonous gas and environmental hazard, is emerging as the third gaseous signaling molecule alongside with nitric oxide and Abbreviations used: ADT, 5-(4-methoxyphenyl) -3H-1, 2-dithiole-3-thione; BBB, blood-brain barrier; EB, Evans blue; H 2 S, hydrogen sulfide; MCAO, middle cerebral artery occlusion; NaHS, sodium hydrosulfide; NOX, NADPH oxidase.