apparently yes, if you beleive my french friend years ago, she would nag me to not drink it, as the gas was harmful, why, i never found out. as i always say in moderation it cant be too bad
I don't know for sure if it is harmful and I can only report from my own personal experience but I have Crohn's Disease (an inflammatory bowel condition) and I went through a phase of drinking carbonated water. I drink water all the time and I tried drinking carbonated water once and over the course of the day, it caused huge problems with my Crohn's and increased my trips to the bathroom! Also, I have a couple of friends who have Irritable Bowel Syndrome and they've both said the same thing about carbonated water. Maybe it's something to do with the gas they use in the carbonating process?
hmm -ive always be advised not to drink carbonated water and on reflection I understand.(just cos i dont like fizzy stuff -much prefer still everything liqiud wise.
I wsnt aware if you opened still water you had to drink it withinn a really short time scale because of the bacteria which rapidly builds up.