Abstract: Composition of Methyl Ethyl Ketone Peroxide as biocide, applied by spraying, for human and veterinary hygiene; of utility in the private sphere and in public health and, particularly, conserving the organic matter of its natural surface decomposition due to the passage of time until the collection for treatment and/or elimination, preventing proliferation of organisms accompanying said situation and the risk of intrinsic infectious contagion. The compositions permitting such biocidal action are a mixture of from 0.01 to 14% Methyl Ethyl Ketone Peroxide, from 1 to 60% glycols or alcohols, from 1 to 60% water and, optionally, from 0 to 10% stabilisers, colourants, scents and/or other additives, from 0 to 10% surfactants and from 0 to 10% acids, conferring on the product a solubility permitting its spraying to act as antiseptic for healthy skin, disinfectant for surfaces and for the maintenance of organic matter and its residues.