A method for standardization of Schisandra chinensis has been developed, which is based on the isolation of the pure lignan fraction with the major content of schizandrol A followed by quantitative spectrophotometric assay with reference to a reliable standard. Solutions used for the primary assay were concentrated and studied by TLC (qualitative analysis). It is established that the content of pure lignans in the S. chinensis extract varies within 0.1–0.2%. Exhaustive extraction with a sequence of solvents showed that air-dry seeds of S. chinensis contain about 1% of pure lignan fraction (predominantly schizandrol A). HPLC analyses showed that the content of schizandrol A in the extract amounted to 0.088% (about 45% of the total purified lignan fraction) and reaches 0.7% in the seeds (about 70% of the purified lignan fraction).