This paper discusses the relationship between Tibetan medical theory and practice with respect to the classification of Materia Medica and the discernment of quality and potency. Based on more than thirty years of experience as a Tibetan medical practitioner, the author describes a number of specific Materia Medica in detail, with an emphasis on how to determine fake from authentic ingredients. The author also offers recommendations and guidance on proper cultivation techniques and conservation methods, in line with Tibetan textual sources on the subject, in combination with empirical knowledge.