Hydrogen sulfide (H2S),a notorious toxic gas with a characteristic smell of rotten eggs,has recently been identified as the third gaseous cellular signal transmitter,in addition to nitric oxide (NO) and carbon monoxide (CO).This magic gas has been recognized to relax vascular smooth muscles,regulate inflammation,mediate neurotransmission,and inhibit insulin signaling [1].H2S can be endogenously produced by enzymes,but its pharmacological mechanism is not fully understood.