Iced tea has been cited as a culprit in formation of kidney stones:
Iced Tea Can Contribute to Painful Kidney Stones
Aug. 2, 2012 — This is the peak season for drinking iced tea, but a Loyola University Medical Center urologist is warning the popular drink can contribute to painful kidney stones.
Iced tea contains high concentrations of oxalate, one of the key chemicals that lead to the formation of kidney stones, a common disorder of the urinary tract that affects about 10 percent of the population in the United States.
"For people who have a tendency to form the most common type of kidney stones, iced tea is one of the worst things to drink," said Dr. John Milner, assistant professor, Department of Urology, Loyola University Chicago Stritch School of Medicine.
The most common cause of kidney stones is not drinking enough fluids. And during the summer, people can become dehydrated from sweating.
Dehydration, combined with increased iced tea consumption, raises the risk of kidney stones, especially in people already at risk........
Iced tea can contribute to painful kidney stones