If you are a fan of iced tea, better watch out, because that refreshing drink for in-between times might just end up taking you to hospital for treatment of shooting pain arising out of kidney stones, recent research suggests.

Iced tea contains very high concentrations of oxalate, one of the key chemicals that lead to the formation of kidney stones. So, would the hot cup of tea also cause the same problems? The study suggests that this could be so.

Tea leaves used to make hot tea also contains equal doses of oxalates. However, nobody consumes a quantity of hot tea large enough to encourage the formation of stones.

"For many people, iced tea is potentially one of the worst things they can drink," says Dr. John Milner, assistant professor at the Department of Urology in the Loyola University Chicago Stritch School of Medicine, Maywood, Illinois.

For people who have a tendency to form kidney stones, it's definitely one of the worst things you can drink. The iced tea has grown dramatically popular with more than two billion gallons consumed a year in the United States, according to the Tea Association of the U.S.A. Nearly 128 Americans drink the beverage daily.

Kidney stones are formed in urinary tract as small crystals due to the accumulation of salts like oxalates. Kidney stones are generally harmless and are usually expelled from the body naturally. However, in some cases the stones grow so bigger that they cannot be expelled through the ureters -- the small tubes that drain urine from the kidney to the bladder.

More men are diagnosed with kidney stones than women with the male of the species being at four times more risk than the females. The risk further increases once men reach their 40s. Postmenopausal women with low estrogen levels and women who have had their ovaries removed also run a higher risk of developing stones.

These stones are small crystals that form from the minerals and salt normally found in the urine in the kidneys or ureters, the small tubes that drain urine from the kidney to the bladder. Most of the time kidney stones are so small that they are harmlessly expelled from the body. But on some occasions, the stones grow to the point that they can become lodged in the ureters.

Failure to drink enough water and other fluids is considered the major cause for kidney stones. The dehydration that is usual in summer combined with increased iced tea consumption raises the risk of kidney stones, especially in people who are prone to develop them.