Significance: In recent times, it has emerged that some dietary sulfur compounds can act on mammalian cell signaling systems via their propensity to release hydrogen sulfide (H2S). H2S plays important biochemical and physiological roles in the heart, gastrointestinal tract, brain, kidney, and immune systems of mammals. Reduced levels of H2S in cells and tissues correlate with a spectrum of pathophysiological conditions, including heart disease, diabetes, obesity, and altered immune function. Recent Advances: In the last decade, researchers have now begun to explore the mechanisms by which dietary-derived sulfur compounds, in addition to cysteine, can act as sources of H2S. This research has led to the identified several compounds, organic sulfides, isothiocyanates, and inorganic sulfur species including sulfate that can act as potential sources of H2S in mammalian cells and tissues. Critical Issues: We have summarised progress made in the identification of dietary factors that can impact on endogenous H2S levels in mammals. We also describe current research focused on how some sulfur molecules present in dietary plants, and associated chemical analogues, act as sources of H2S, and discuss the biological properties of these molecules as studied in a range of in vitro and in vivo systems. Future Directions: The identification of sulfur compounds in edible plants that can act as novel H2S releasing molecules is intriguing. Research in this area could inform future studies exploring the impact of diet on H2S levels in mammalian systems. Despite recent progress, additional work is needed to determine the mechanisms by which H2S is released from these molecules following ingestions of dietary plants in humans, whether the amounts of H2S produced is of physiological significance following the metabolism of these compounds in vivo, and if diet could be used to manipulated H2S levels in humans. Importantly, this will lead to a better understanding of the biological significance of H2S generated from dietary sources, and this information could be used in the development of plant breeding initiatives to increase the levels of H2S releasing sulfur compounds in crops, or inform dietary intervention strategies that could be used to alter the levels of H2S in humans
