Rotavirus is one of the universal viruses that causes diarrhea(acute gastroenteritis) in the worldwide, and the infections are sporadically accompanied with critical illness. Ten percent of affected individuals are admitted to hospitals. The complications are commonly serious dehydration, several diseases of central nervous system, sepsis and postrenal insufficiency accompanied with renal stone. Two safety and effective vaccinations were implemented to prevent infections. According to the overseas guideline management for estimations for the severity and treatment by oral rehydration solution are recommended.