Nitrate is ubiquitous. It is present in water, soil, plants and food, and is also a normal human metabolite. The main external sources of nitrate are vegetables and drinking water. This book examines the relationship between nitrates and human health. During the last 50 years or so, nitrate has been feared as the source of the rare condition called methaemoglobinaemia, or "blue baby syndrome", for young infants. Nitrate has also been implicated with causing cancer, through increased formation of carcinogenic compounds. Both claims are based on dubious evidence. This book sets out research results to disprove these assumptions, and goes on to explore the beneficial effects of nitrate in preventing infections, cancer and cardiovascular diseases. It is essential reading for researchers in medicine, and those in agriculture and food industries.