This book provides a comprehensive description of the application of clay minerals as disinfectants and the ingredients of medicines. While the presently available literature highlights one or two aspects of medicinal clays, a comprehensive text on all their major pharmaceutical applications is lacking. This book endeavors to fill up this lacuna. It further elucidates the properties of clay minerals that facilitate their application in the protection of human health, and how these properties are related to the chemical compositions and internal structures of selected mineral groups, thus revealing to the students, teachers and researchers the underlying relationship of seemingly different disciplines like mineralogy, material science and medical science. The thought-provoking questions added at the end of each chapter will give the readers a better insight of this subject. The tangible definitions and explanations of all the relevant scientific terms provided in this book, both within the text and in a glossary list at the end, are expected to help the beginners to develop a clear-cut understanding regarding different aspects of the subject and clear any confusion resulting from the ambiguous usage of terms in the existing literature.