The substantial biological importance of gaseous mediators in various physiological-pathological conditions has been realized only recently, but to date, the detailed mechanisms involved remain elusive. The publication at hand contains 16 overviews written by a panel of experts who summarize the current knowledge and provide fundamental insights into the roles of gaseous molecules in signal transduction in biological systems. The first part provides a comprehensive overview on gaseous mediators in health and disease. In the second part, the medical application of various molecules such as nitric oxide, carbon monoxide, hydrogen sulfide, hydrogen, acetone and phytoncide are discussed. Furthermore, articles on skin gas biology and Carbon-13 (13C), especially clinical applications of 13C-labeled substrate are included. This book provides valuable information not only for basic researchers in physiology and biochemistry, but also for gastroenterologists and clinicians who wish to learn more about the role of gaseous mediators.