why drink too much distilled water is not good to our health

This should be a biological question.
Distilled water will increase the water potential of solution. As too much distilled water enters our blood stream, the water potential of our blood is increased. The water will enter the blood cells / other cells by osmosis. As the pressure is built up inside the cells because of the entry of water, the cells will eventually burst. Losing too many cells is not a good thing to our body.

2008-04-11 16:26:09 補充：
To whoever replied to me:
He said 'too much distilled water'
E.g. if you drink 10L distilled water in an hour, I don't think your kidney can work so quickly

我很難回答你到底是對還是不對
主要是每個人的身體特性並不相同
蒸餾水不含礦物質 主要是水 滲透壓較低
長期喝蒸餾水 比較會趨向礦物質缺乏
若是正常的喝水量 蒸餾水並不會導致身體的問題
甚至高一些也不會怎樣
因為身體會調節血液滲透壓 主要是靠腎臟
腎臟會感受滲透壓的改變 而調節尿液來平衡血液的滲透壓
若是一次大量的喝下水(蒸餾水) 有可能導致腎臟來不及反應
變成水中毒 也就是鹼中毒
但是有些人的腎臟對血液的滲透壓改變很敏感
有些人就比較遲鈍
這會影響到水在身體內停留的時間
所以有些人喝水容易水腫 有些人不會
結論是 不是短時間大量攝取 都沒有影響性

reply to yiki1991.
Acturally, there is homeostasis to regulate the water potential.