Gastroenteritis literally means inflammation of the gastrointestinal tract. Viral gastroenteritis is also called "stomach flu." It is extremely common, especially in children, and is highly contagious. Bacterial gastroenteritis is also known as "food poisoning" and is caused by food that has been prepared or stored improperly. Gastroenteritis can also be caused by ingestion of drugs or chemical toxins (e.g. metals, plant substances).