Chemical characteristics, protein-adsorbing capacity, chemical modifications and utilization of condensed tannis from tree barks were reviewed. Various aspects relating to the chemistry of these compounds and prospects for their utilization were discussed. Condensed tannins from Quercus falcata, Salix sieboldiana and most of the Japanese conifers consist mainly of procyanidins and those from Acacia mearnsii of prorobinetinidins. The protein-adsorbing capacity of condensed tannins is closely related to their molecular weights and the positions of phenolic hydroxyl groups in the B-ring. The most effective hydroxyl group is located in the paraposition. In the reactions of catechin, the pyran ring is cleaved by alkaline treatment at 40℃ or phenolation in the presence of BF₃. The latter reaction can be effective for opening the pyran ring selectively. The tannins can be processed for utilization as cold-setting adhesives, polyurethane foams and adsorbents of heavy metal ions. Prospects for uses of condensed tannins include applications to biologically active compounds and functional materials.