The structural diversity and high reactivity of phenolic compounds synthesized by higher plants and the toxicity of many intermediate products of their hydrolysis or oxidation causes that they may play an important role in the resistance of plants to different stresses, including feeding by spider mites (Acarina: Tetranychidae). The results of our studies as well as literature data indicate that the feeding of these pests brings about the induction of a defensive response. The active defensive mechanism of a plant is determined by different phenolic compounds and enzymes involved in their synthesis (PAL) and oxidation (PPO, POX). The induced defensive mechanism is usually associated with some degree of specificity. In consequence, the induced resistance reactions, by limiting the further development of the mite pests, protect the plant from further damage.