Prolonged cucumber cultivation in the same substrates leads to accumulation of phytotoxic phenolic compounds. Introduction of sweet pepper as an aftercrop eliminates substrate phytotoxicity.The aim of the study was to examine whether in sweet pepper detoxication of substrate phenols occurs by means of the glucosylation process. The examined materials were substrates differing in phytotoxicity level, and sweet pepper plants grown on these substrates. Substrate phytotoxicity was obtained by means of either repeated cucumber cultivation or by phenolic acid addition. During the vegetative growth phase of sweet pepper, the phytotoxicity and phenolic compound levels in the substrate, and the glucosylated phenol contents in above-ground plant parts were determined.Results showed that sweet pepper responds to an increased presence of phenols in the substrate by an intensified glucosylation.