The combined use of foliar treatment with the biologically active substance Reglalg and microelements B, Zn, Mn, Mo has a positive effect on the processes of accumulation of chemical compounds - indicators of the quality of plum fruits and their consumption in the post-harvest period. It is shown that the treatment of plum trees with these preparations promotes the accumulation of solids, total sugar and vitamin C in plum fruits at the time of harvest, which contributes to the formation of optimal quality and duration of storage of fruits. During storage, a slowdown in the dynamics of biodegradation and consumption of these compounds was found in fruits harvested from treated trees compared to untreated ones, which indicates an increase in fruit viability.