Diarrhea and nausea are caused by acute gastroenteritis, gastrointestinal flu, and bacterial dysentery. The intestinal system is impaired in function due to ischemia and hypoxia when the abdomen is cold or chilled. Some people also have inflammation of the intestinal mucosa, thus inducing acute gastroenteritis. Patients with acute gastroenteritis experience diarrhea and nausea due to hypermotility and increased internal pressure in the digestive system as a result of inflammatory stimulation of the intestinal mucosa. When the Coxsackie virus enters the digestive system along with saliva, it can damage the intestinal mucosa and induce gastrointestinal flu, with abdominal pain, diarrhea, nausea, vomiting, dizziness, and headache as the main symptoms during the illness. Eating unclean food in the diet will lead to a part of the bacteria into the digestive system, and may even induce bacillary dysentery. Bacterial dysentery is characterized by severe abdominal pain, diarrhea and nausea and vomiting.