The aim is to study the variability of the content of Bidens cernua herb biologically active substances in the storage process. The content of biologically active substances (polysaccharides and flavonoids) in Bidens cernua herb during storage for two years was monitored every 3 months for two series: series A simulated the storage of medicinal plant raw materials prior to their use in industrial production, series B completely repeated the most frequently used packaging for herbal medicines. Additionally, the content of the dominant flavonoids quercitrin and luteolin-O-7-glucoside, as well as the product of its hydrolysis, luteolin, was assessed annually by liquid chromatography. It has been established that a decrease in the polysaccharides content by no more than 5% in series A was observed within 9 months, in series B - within 12 months. After 24 months of storage, the polysaccharides content in Bidens cernua herb was higher in series B. A decrease in the content of the sum of flavonoids by no more than 5% was observed within 6 months for both series. After 24 months, the content of the sum of flavonoids, as well as quercitrin and luteolin-O-7-glucoside, was higher in series A. Thus, the choice of the optimal packaging for storing Bidens cernua herb will be determined by the requirement for the quality of medicinal plant raw materials in terms of the content of biologically active substances, which, in its turn, will determine the expected pharmacological activity of this type of medicinal plant material.