The preparation includes diverse biological substances obtained from multistep pro-cessing of codfish liver. Previous studies demonstrated strong anti-inflammatory ac-tivity in contact dermatitis model [1]. The purpose of this work was to characterize in outline composition and possible action mechanism of the preparation. Primary frac-tionation on molecular weight (MW) and estimation of effect on functional activity of professional phagocytes (on their capability to produce reactive oxygen species, ROS) were carried out. Lipophilic fraction was separated from aqueous preparation suspension by centrifugation; other fractions were obtained by sequential ultrafiltrational exclusion of components with MW exceeding 10 kDa and 1 kDa. The ratio of fractions (fig.1) demonstrates the prevalent presence (54%) of low-MW components, which showed no reliable effect on ROS production (fig.2). The strongest effect was detected in lipophilic fraction ("lipids", fig. 2) and this effect four times exceeds one of total prepara