hydrogen sulfide (h2s), regarded as the third gasotransmitter, plays diverse physiological and pathological roles in the body along with another two gasotransmitters, including nitric oxide (no) and carbon monoxide (co). in the liver, cystathionine gamma-lyase (cse) is the main enzyme to generate h2s. the functions of h2s in the liver are largely unknown even though many studies showed h2s and cse are important in redox control of liver. s-sulfhydration, a novel post-translational modification of proteins, is now considered as an important mechanism of h2s effects under various physiological and pathological conditions.