Gastroenteritis is the inflammation of the gastrointestinal tract, which includes the stomach and the small intestine. It is often called "stomach flu". Its symptoms mainly include abdominal pain, diarrhea, dehydration, fever and vomiting. Rotavirus and norovirus are two of the most common causes of gastroenteritis. The transmission of both these viruses takes place through the fecal-oral route. Lack of adequate sanitation, open defecation and poor hygiene practices are the main causes of disease transmission. The methods of prevention include proper hand washing with soap, proper disposal of human waste and drinking clean water. Rotavirus vaccine is effective in preventing rotavirus in children. This book discusses the fundamentals as well as modern approaches of diagnosing and managing gastroenteritis. It will also provide interesting topics for research, which interested readers can take up. For all those who are interested in gastroenteritis, this book can prove to be an essential guide.