As the major sulfide emitted to the atmosphere by the marine microorganisms (Wolfe et al., 1999; Todd et al., 2009), DMS has been historically recognized in the atmospheric circulation (Cameron‐Smith et al., 2011). Although current studies have focused on its role in the lower organisms (Wolfe et al., 1999; Sunda et al., 2002; Todd et al., 2007), DMS has been found in the blood circulation of mammals, including human being (DeBose & Nevitt, 2008; Mochalski et al., 2014), and recognized as a potent chemoattractant for animals and a disgusting component of bad breath (DeBose & Nevitt, 2008; Nevitt, 2008). However, other physiological role of DMS in mammals remains to be unmasked. We found that at near‐physiological level, DMS reduced the level of ROS in cell lines and alleviated oxidative stress. Thus, DMS may emerge as a physiologic cytoprotectant against oxidative stress‐induced cell death and aging.