Yes - this is something I should ALWAYS do, as I never drink enough anyway! (It's never too late to start a good habit!) Thanks.
Update 8-11-06
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It's quite incredible how water/fluid drives away that headache, I've found. I'm now on Day 6 of my fast/cleanse, and I find that if a headache starts to niggle, I just need to drink a couple of mugs of herbal tea or glasses of water, and it's gone! Miraculous!