The aim of this work was to establish pharmacognostic parameters of Casearia sylvestris Swartz, known in the folk medicine as guaçatonga, to improve the quality control of the drug. The species is official in the Farmacopéia Brasileira I, where only macroscopic and microscopic characters are described. We suggest new parameters for ash content, water extract and evaluation of tannins, as well as its profile in thin layer chromatography.