The content of calcium, magnesium, potassium and lead was determined in galls of six eriophyid mite species. Several changes in the content of these chemical elements (increasing and decreasing of their content) were found in plant tissues injured by eriophyid mites. The most significant difference concerned an increase in the content of potassium which was found in the galls of Eriophyes acericola on Acer saccharinum.