Diarrhea is a condition in which a person suffers from loose or liquid bowel movements. The primary cause of diarrhea is an infection in the intestines. The infection may be caused by a bacteria, virus or parasite. It may also be caused by non-infectious health conditions such as lactose intolerance, inflammatory bowel disease, hyperthyroidism, etc. Replacing the loss of fluids and salts through oral rehydration therapy or intravenous rehydration therapy is the most common treatment method. In some chronic cases, antibiotics may also be used to treat diarrhea. This book unravels the recent studies in this medical condition. It aims to elucidate the causes, diagnosis and treatment of the different forms of diarrhea. This book is an essential guide for clinicians, doctors and medical students.