Gastroenteritis or infectious diarrhea is a medical condition from inflammation (-itis) of the gastrointestinal tract that involves both the stomach (gastro -) and the small intestine (entero -). It causes some combination of diarrhea, vomiting, and abdominal pain and cramping. Dehydration may occur as a result. Gastroenteritis has been referred to as gastro, stomach bug, and stomach virus. Although unrelated to influenza, it has also been called stomach flu and gastric flu.