The present invention generally relates to deuterium-enriched aldehydes, compositions comprising deuterium-enriched aldehydes, and methods for slowing the rate of aldehyde autoxidation. In one aspect, the present invention provides a composition comprising a compound of structure 1:wherein: there are at least 6×1018 molecules of the aldehyde and Rx is hydrogen, wherein the deuterium isotope in Rx is in an amount greater than 0.10 percent of the hydrogen atoms present in Rx.