Diarrhea is a characteristic sign of gastroenteritis. As bacteria enter the digestive tract, they start acting on the partly digested food. The toxins that may either be present in the contaminated food, or may be generated as the bacteria act on the contents of the stomach or the intestinal tract, may further cause inflammation of the stomach and the intestines. The digestive process would naturally be adversely affected on account of inflammation. Since the absorption of nutrients or water may be impacted, one is most likely to suffer from watery stools or diarrhea. Vomiting, nausea, bloating or abdominal cramping may also be experienced by the sufferer. Since there may be a significant loss of fluids owing to diarrhea or vomiting, one may also feel lightheaded or weak due to dehydration. One may also suffer from loss of appetite, dry mouth, nausea or fever. In severe cases, traces of blood may be present in stools.