Prebiotics and Probiotics is a concise, well-written and easily readable guide to two important nutritional components that can have a markedly beneficial effect on human health, particularly that of the digestive tract and the immune system. The delicate balance in the numbers and types of intestinal bacteria that should exist in healthy people can be disrupted by several factors, including poor diet, natural aging, stress and antibiotic therapy. A more alkaline environment in the gut, for example, can cause a preponderance of “bad” bacteria and a bacterial imbalance that results in the preponderance or overgrowth of bad bacteria and yeast within the gut is known as intestinal dyspepsia. The latter is just one of the many subjects covered in this book. The Introduction provides an overview of the book and sets the stage for each chapter. Chapter 1, The Digestive Tract, discusses the anatomy and physiology of the gastrointestinal system and indicates how all components work together to provide nutrition for the body. It also provides an overview of the microbiota or bacterial components that reside within this complex system. Chapter 2, Bacteria, talks about the many different types of bacteria that exist within the human body and indicates the differences between the various “good” and “bad” bacteria that co-exist within gut, the oral cavity and elsewhere in the body. It makes clear the role of “good” bacteria in the body and how “bad” bacteria can interfere with the proper functioning of “good” bacteria. The importance of bacteria to the health and efficiency of the immune system is stressed. The nature of the microbiological entities known as probiotics is discussed. Chapter 3, Prebiotics, discusses the digestion of food and how dietary differences can influence systemic as well as gastric health. Although prebiotics, often referred to as dietary fiber, is infrequently discussed, they are in fact vital to gastric health and well-being. For example, slow intestinal passage of digested foodstuffs, i.e. one cause of constipation, is relieved by dietary fiber (prebiotics). Most prebiotics are carbohydrates that are fermented in the large intestine and the gases produced during fermentation increase the volume and reduce the transit time of the fecal material in the large intestine. Prebiotics also increase the water content and lower the pH in the intestine, both effects enhance gut motility, reduce transit time, and help relieve constipation. Chapter 4, Probiotics, starts with an introduction on how the importance of probiotics to health and vitality was discovered by a physician working in Bulgaria over a century ago and relates how, until recently, the importance of this finding was largely neglected by modern medical science. In fact, the incredible potential benefits to systemic health of regular consumption of probiotics are only now being evaluated by research centers throughout the world. The types of probiotics that occur in fermented milk products such as yoghurt and Kefir are discussed in detail and the role of the multitude of probiotics in alleviating the problems associated with a wide variety of diseases is considered. Finally, there is a glossary of scientific and medical terms to help the reader understand the sometimes complex issues and important terms used in any discussion of nutrition, diet and health as well as providing a handy reference guide to the book content.