The invention relates to medicine. The inventive method for treating human diseases associated with an increased deoxyribonucleic acid content in extracellular spaces of tissues and organs, consists in orally injecting a DNA ferment in a quantity of 20 000-500 000 Kunz units in a day per 1 kg of the body mass. The single dose of the inventive medicinal preparation for treating human diseases associated with an increased deoxyribonucleic acid content in extracellular spaces of tissues and organs comprises 20 000-500 000 Kunz units of the DNAse ferment. The oral administration of the above-mentioned important doses of the preparation only allows the catalytically significant amount of DNAse to be absorbed into the systemic circulation in such a way that the dose-dependent treating effect thereof is exhibited.
