green tea does contain caffiene, and caffeine is a stimulant and a diuretic. it also contains lots of good stuff, like antioxidants.
drinking lots of it can mean the caffeine affects you (especially if you drink it in the afternoons and evenings) and it would also mean the diuretic effect would be happening (weeeeee!
) the diuretic effect can hinder fluid intake... as iyour body is expelling it again.
like anything, don't overdo it. mix your green tea intake with plain old water (warm or hot water is actually very yummy on it's own in winter!) and maybe mix in a few other herbal teas as well. i love rosehip and hibiscus tea.