The latest cutting-edge research findings published in highly influential journals have greatly advanced our current understanding of hydrogen peroxide (H₂O₂), a notable reactive oxygen species, in chemistry, biology, and medicine. In this context, recent studies by J.K. Lee et al., published in Proc Natl Acad Sci USA, discovered a novel mechanism of spontaneous production of H₂O₂ from pure water in the absence of catalysts or external electric field. This discovery by J.K. Lee et al. has changed our view on the chemical connection between H₂O₂ and H₂O though the biological significance of the discovery remains unknown. REFERENCES Hopkins RZ, Li YR. Essentials of Free Radical Biology and Medicine. Cell Med Press, Raleigh, NC, USA. 2017. Hopkins RZ. Hydrogen peroxide in biology and medicine: an overview. React Oxyg Species (Apex) 2017; 3(7):26–37. doi: https://dx.doi.org/10.20455/ros.2017.809. Bergman P, Parise B, Liseau R, Larsson B, Olofsson H, Menten KM, et al. Detection of interstellar hydrogen peroxide. Astronomy Astrophysics 2011; 531:L8. doi: https://dx.doi.org/10.1051/0004-6361/201117170. Lee JK, Walker KL, Han HS, Kang J, Prinz FB, Waymouth RM, et al. Spontaneous generation of hydrogen peroxide from aqueous microdroplets. Proc Natl Acad Sci USA 2019; 116(39):19294‒8. doi: https://dx.doi.org/10.1073/pnas.1911883116. Lee JK, Han HS, Chaikasetsin S, Marron DP, Waymouth RM, Prinz FB, et al. Condensing water vapor to droplets generates hydrogen peroxide. Proc Natl Acad Sci USA 2020; 117(49):30934‒41. doi: https://dx.doi.org/10.1073/pnas.2020158117.