Relevance and goals. Milk thistle fruit Silybum marianum fructus -plant raw materials used for the production of drugs and biologically active additives (BAD) hepatoprotective and antitoxic action. Various qualitative composition of flavolignans in raw materials creates certain difficulties in its standardization. The purpose of the work was improvement of approaches to standardization of fruits of milk thistle, comparative characteristics and harmonization of methods of qualitative and quantitative analysis of the determination of flavolignans.