Hydrogen sulfide (H 2

Hydrogen sulfide (H(2)S) is a newly recognized signaling molecule with very potent cytoprotective actions. The fields of H(2)S physiology and pharmacology have been rapidly growing in recent years, but a number of fundamental issues must be addressed to advance our understanding of the biology and clinical potential of H(2)S in the future. Hydrogen sulfide releasing agents (also known as H(2)S donors) have been widely used in the field. These compounds are not only useful research tools, but also potential therapeutic agents. It is therefore important to study the chemistry and pharmacology of exogenous H(2)S and to be aware of the limitations associated with the choice of donors used to generate H(2)S in vitro and in vivo. In this review we summarized the developments and limitations of current available donors including H(2)S gas, sulfide salts, garlic-derived sulfur compounds, Lawesson’s reagent/analogs, 1,2-dithiole-3-thiones, thiol-activated donors, photo-caged donors, and thioamino acids. Some biological applications of these donors were also discussed