This study presents a detailed pharmacognostical study of the root and leaf of the crude drug Clerodendrum viscosum Vent. (Verbenaceae), an important plant in the Indian system of medicine. The root and leaf samples were studied using light and confocal microscopy, WHO recommended-physicochemical determinations, and authentic phytochemical procedures. The physicochemical, morphological, and histological parameters presented in this paper may be proposed as parameters to establish the authenticity of C. viscosum root and leaf, and may possibly help to differentiate the drug from its other species.