(May be a dupe - the Search engine won't tell me. Fascinating article, though.)
http://www.smh.com.au/articles/2003/08/22/1061529331538.html?from=storyrhsActors must expect their excessive drinking habits to be breakfast table gossip, especially if they become too drunk to perform. But the curious case of Anthony Andrews, whose addiction to water almost killed him, must rank as one of the more bizarre forms of theatrical unwellness.
<snip>
As temperatures soared during the play's mid-summer run, Andrews's three-litres-a-day habit increased to five or six litres as he struggled to refresh his vocal cords. On days when there was a matinee as well as an evening performance, he probably got through eight litres of water - all the while assuming he was doing himself good.
In fact, he was building up a condition known as hyponatremia, which is usually associated with ecstasy-users and marathon runners, and often mistaken for heat exhaustion.