Nausea, vomiting and headache are mainly caused by gastrointestinal type of cold, but some people also have encephalitis and meningitis. Gastrointestinal flu is a special type of gastroenteritis, and the disease is directly related to a viral infection of the gastrointestinal system. The symptoms of gastroenteritis are not only related to the digestive system, such as nausea, vomiting and diarrhea, but also to the symptoms of cold. The onset of gastrointestinal colds is associated with viral infections and requires treatment with antiviral drugs. Encephalitis and meningitis are diseases caused by viral infections, which affect the central nervous system of patients during the disease. Since the gastrointestinal system is controlled by the central nervous system, patients will also experience symptoms of the gastrointestinal system, and will also show symptoms such as nausea, vomiting and headache.