Quality control of herbal medicines (HMs) can be performed using a "component-based" approach and "pattern-based" approach. The quality control of HMs has become more challenging and demanding. The quality considerations of drugs are the most stringent among all consumer products. Quality control for the efficacy and safety of herbal products is of paramount importance. Quality control is based on three important pharmacopoeial definitions, that is, identity, purity, and content or assay. Purity is closely linked with the safe use of drugs and deals with factors such as ash values, contaminants, and heavy metals. To prove the identity and purity, criteria such as the type of preparation, sensory properties, physical constants, adulteration, contaminants, moisture, ash content, and solvent residues have to be checked. Herbal medicinal drugs may have a single active constituent or the entire herb source may be considered as the medicinal product.