Hydrogen sulfide (H2S) has emerged as an important gas signalling molecule in a series of organs/tissues, on the diseases of which it plays protective roles, such as proangiogenic effects in ischemic tissues, antiapoptotic effects in the cardiomyocytes, regularization of fatal arrhythmia in myocardial infarction, amelioration of inflammation in autoimmune diseases, modification of neuronal transmission, increase in sodium excretion from the kidney, and amelioration of insulin resistance, etc. This book focuses on the effect of hydrogen sulfide in cardiovascular system, immune system, nervous system, kidney, as well as on the metabolism of glucose and lipids and regulation of ion channels and so on. This book also provides the advances in the understanding of endogenous H2S metabolism and H2S protein targets, as well as H2S donors. It will benefit researchers in both academics and industry working on the underlying mechanism of H2S field and the future of translational medicine of H2S.