The invention concerns a preservative for ornamental cut flowers in the form of a mixture of compounds containing commercial sugar, citric acid, sodium citrate, germicide, ethylene synthesis inhibitor and humectant, which is prepared to be diluted in a liter of water and to preserve the cut carnations therein. The useful commercial life of the cut flowers is thereby considerably enhanced. The main advantages provided by said composition in comparison with commercially available compounds is that it exhibits greater effectiveness in retarding senescence or aging off the cut flower and the fact that it does not contain compounds that may pollute the environment or be harmful to the health of humans or animals.