This document discusses drug adulteration in herbal medicines. It defines adulteration as substituting the original medicinal plant partially or wholly with other similar-looking substances that are inferior in quality. Adulteration can occur intentionally for commercial gain or unintentionally due to misidentification, lack of knowledge about the authentic plant, morphological similarities between plants, lack of the authentic plant, or careless collection practices. The document outlines various types of intentional and unintentional adulteration and provides examples.