Wow.. so far in this thread there is a bit of bullshit, a lack of knowledge, and no help for the original poster (besides ANC & Psychedelics and Chronic).
First off (let's get real basic):
Ecstasy is Methylenedioxy Methamphetamine (MDMA)
It's a Stimulant (as you can tell from the "methamphetamine")
Yeah, it is always good to stay hydrated, regardless of the chemical you are on, the reason people complain about this is because MDMA raises your body temperature making most people get a little stupid watter happy. lol. All you need to do is stay hydrated, meaning, don't drink an excessive amount that would be abnormal compared to your daily routine. Another side effect from MDMA is drinking too much water! Like I said, people's body temp. raises and they drink like a horse, this isn't necessary. Drinking too much water can lead to Hyponatremia (essentially, water poisoning, or a lack of vitamins and minerals present in the body).
The problem with "ecstasy" is that when in pill form, it is cut. What is it cut with? That is hard if not impossible to say if you don't have reagent testing equipment. So if you can find "Molly" or ask for "MDMA" you'll not have to deal with potentially dangerous or unpleasant cutting agents.
This is pretty basic, if you want to know more or have other questions, the link below will guide you through probably anything you could ask. If it doesn't, come back here.
http://www.erowid.org/chemicals/mdma/mdma.shtml
