Lignans in the fruits of Schizandra (syn. Schisandra MICHX.) chinensis BAILL. (Schisandraceae) were quantitatively analysed by high performance liquid chromatography using a reversed-phase stationary phase. It was found that the commercially available samples considered to be collected in central and northern parts in Korea or China contained schizandrin (I), gomisin N (IX) and gomisin A (IV) as main components, while those in the samples collected in Japan were schizandrin (I) and deoxyscizandrin (VII). Seasonal variations of lignan contents in the fruits of S. chinensis collected in Nagano prefecture were also investigated. It became clear that all of the lignans were produced in the seed with its formation and that the contents gradually decreased in the same constituent ratio.