This book focuses on presenting the current scientific evidence of biomolecular effects of selected herbs in relation to clinical outcomes and therapy for promotion of human health. Whereas many herbal medicines are made by mixing different herbs, the focus in this book is on single herb. The herbs selected cover a wide range and include flowering herbs, leaves, and leaf exudate (Aloe vera), fruits, roots and rhizomes. The use of herbs in relation to cardiovascular disease, cancer, diabetes, skin disorders, and neurodegenerative disease. The ethics of using herbal medicine and its integration into modern, evidence-based medicine. Finally, the use of new technologies of mass spectrometry and chemometric fingerprinting in the authentication of herbs is presented. These technologies will bring a previously unknown level of quality control to the production of herbal extracts. Currently, many commercially available herbal products are uncharacterized and of questionable quality or content. The composition of natural products such as herbs can vary greatly with season, growing conditions, preparation, and storage. However, there is also adulteration, contamination, and misidentification of herbs and herbal products. Improved quality control techniques and processes for the identification of herbs and the establishment of characteristic chemical “fingerprints” for herbs and herbal medicines are badly needed.