The present invention provides a citral acetal capable of sustaining a lemon aroma unique to citral and a perfume composition comprising the citral acetal, as well as an LDH inhibitor and a deodorant, cosmetics and a skin agent for external application, comprising the LDH inhibitor. The citral acetal of the present invention is represented by formula (1): ##STR1## wherein the wavy line represents a cis and/or trans form, and R represents a C.sub.1, to C.sub.9, linear or branched alkyl group.