I bogged recently about five medical myths, one of which was drinking 8 glasses of water a day (or similarly large amounts) is good for one's health. I cited a review of the literature by Heinz Valtin that found no evidence for the claim. Now Dan Negoianu and Stanley Goldfarb have conducted a similar review (no free version alas), that comes to exactly the same conclusion. In other words, there really doesn't seem to be any evidence that drinking large amounts of water is a good idea. Encouragingly, Negoianu and Goldfarb's study has received a large amount of media attention, so hopefully this myth's grip on the public will be loosened somewhat.
(See also: the Reuters piece on the article).