In a modest circumstance,one ingests and eliminates 2-3 liter water per day to keep body fluid balance.Dehydration occurs if one drinks less or loses more water.Ancient Chinese looks on water beyond this input-output balance in various functional ways as drive of life,while emerging biomedicine evidences also indicate that water ingestion is of functional roles in heahh enhancing and disease preventing in addition to a short-term euhydration maintaining.The presentation will review hydration physiology and recommendations for water intakes in China and other countries,and discuss the related evidence bases.Rationally,an evidence-base recommendation for water drinking might primarily base on the prevention of dehydration of more than 2% bodyweight.On the other hand,facing potential health benefits of extra water ingestion,although current evidence strength is weak,what should be recommended for the public if risk may be neglected almost?