The work aimed to determine the chemical composition of dry stevia leaves, as well as the effect of temperature and mechanochemical activation on organoleptic and physicochemical parameters during their processing. The studies used the methods of liquid chromatography and amperometric detection. Mechanochemical activation of dry stevia leaves was carried out in a vertical rotary-roll disintegrator. The authors describe the quantitative content of proteins, lipids, carbohydrates, dietary fibers, extractives, tannins, and ash. The paper presents the dependencies of the influence of mechanochemical activation modes on the content of diterpene glycosides and triterpene saponins and the influence of mechanochemical activation modes on the content of soluble pectin and the water-soluble fraction of proteins. The results obtained confirm the nutritional value of the product obtained after processing in a rotary-roller disintegrator and determine the prospects for its use as a source of valuable substances in the production of functional food products.