This article shows the possibility of using a biotechnological method to obtain biologically active compounds based on in vitro cultivation of callus cultures. The callus biomass of Adonis vernalis was obtained in vitro by using the biotechnological method. The extracts based on callus biomass of Adonis vernalis were obtained. The content of flavonoids and phenolic compounds was determined. The antioxidant activity of callus biomass of Adonis vernalis has also been studied. The research results show that the content of biologically active substances and biological activity in callus biomass does not differ from plant raw materials.