Topical use in the preservation of a human or animal body of a composition including: (a) at least one polyoxymethylene dialkyl ether of formula: R-(OCH 2) n -OR' wherein R and R', identical or different, represent a linear or branched alkyl radical comprising 1 to 5 carbon atoms and n is an index with a value comprised between 1 and 8, and/or at least one dialdehyde acetal of formula: where R 2, R 3, R 4 and R 5 designate independently a linear or branched alkyl radical comprising 1 to 8 carbon atoms, or R 2 and R 5 and/or R 3 and R 4 form together and with the two oxygen atoms to which they are attached a saturated or unsaturated heterocycle with 5 or 6 members optionally substituted by one or more groups chosen from OH, CH 2 OH or a linear or branched alkyl radical comprising 1 to 8 carbon atoms; and R 1 represents a CH-R 6 -CH group where R 6 forms a bond or represents a linear or branched alkylene radical, comprising 1 to 5 carbon atoms or a saturated or unsaturated carbocycle comprising 3 to 8 carbon atoms; or R 1 is a saturated or unsaturated carbocycle comprising 3 to 8 carbon atoms, (b) at least one biocidal agent chosen from: formaldehyde, sulfur dioxide, sodium hydrogensulfite, sodium disulfite, sodium sulfite, potassium sulfite, potassium disulfite, bronopol, 1,2-benzisothiazol-3 -one, dodecylguanidine monohydrochloride, glutaral, methylene dithiocyanate, the polymer of N,N"'-1,6-hexanediylbis[N'-cyanoguanidine] and of hexa-methylenediamine/polyhexamethylene biguanide monohydrochloride, 2-butanone peroxide, m-phenoxybenzyl 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate/permethrin, quaternary ammonium chlorides, bis(trichloromethyl) sulfone, boric acid, N,N-diethyl-m-toluamide, 2-methyl-2H-isothiazol-3-one, the compounds of formula (C 3 H 4 O) n ·(C 3 H 4 O 2) m where n > m, polyvinylpyrrolidone iodide and their mixtures, and (c) optionally at least one propenetrating agent. (a) at least one polyoxymethylene dialkyl ether of formula: R-(OCH 2) n -OR' wherein R and R', identical or different, represent a linear or branched alkyl radical comprising 1 to 5 carbon atoms and n is an index with a value comprised between 1 and 8, and/or at least one dialdehyde acetal of formula: where R 2, R 3, R 4 and R 5 designate independently a linear or branched alkyl radical comprising 1 to 8 carbon atoms, or R 2 and R 5 and/or R 3 and R 4 form together and with the two oxygen atoms to which they are attached a saturated or unsaturated heterocycle with 5 or 6 members optionally substituted by one or more groups chosen from OH, CH 2 OH or a linear or branched alkyl radical comprising 1 to 8 carbon atoms; and R 1 represents a CH-R 6 -CH group where R 6 forms a bond or represents a linear or branched alkylene radical, comprising 1 to 5 carbon atoms or a saturated or unsaturated carbocycle comprising 3 to 8 carbon atoms; or R 1 is a saturated or unsaturated carbocycle comprising 3 to 8 carbon atoms, (b) at least one biocidal agent chosen from: formaldehyde, sulfur dioxide, sodium hydrogensulfite, sodium disulfite, sodium sulfite, potassium sulfite, potassium disulfite, bronopol, 1,2-benzisothiazol-3 -one, dodecylguanidine monohydrochloride, glutaral, methylene dithiocyanate, the polymer of N,N"'-1,6-hexanediylbis[N'-cyanoguanidine] and of hexa-methylenediamine/polyhexamethylene biguanide monohydrochloride, 2-butanone peroxide, m-phenoxybenzyl 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate/permethrin, quaternary ammonium chlorides, bis(trichloromethyl) sulfone, boric acid, N,N-diethyl-m-toluamide, 2-methyl-2H-isothiazol-3-one, the compounds of formula (C 3 H 4 O) n ·(C 3 H 4 O 2) m where n > m, polyvinylpyrrolidone iodide and their mixtures, and (c) optionally at least one propenetrating agent.