The substitution of materia medica in Tibetan medicine was an important issue in the past, and still is today. This article offers a brief survey of references found in Tibetan written sources, and discusses the only three Tibetan treatises that deal exclusively with the subject. It explores the underlying modes of substitution, and provides insights into the criteria that are used to determine suitable substitutes. Ultimately it demonstrates that seven criteria—taste, healing potential, type, substance, name, shape, and smell—are used to determine an appropriate substitute for rare or expensive materia medica in the Tibetan medical tradition
