A liquid concentrate for preserving cosmetic products includes a combination of carboxylic acid salts chosen from the salts of benzoic acid, propionic acid, salicylic acid, sorbic acid, 4-hydroxybenzoic acid, dehydracetic acid, formic acid or 10-undecylenic acid and alcohols chosen from 2-phenozyethanol, benzyl alcohol, phenethyl alcohol, 1-phenoxypropan-2-ol, 3-(4-chlorophenoxy)-1,2-propanediol, chlorobutanol or 2,4-dichlorobenzyl alcohol in a solvent, where the active ingredient content is greater than 45% by weight.