Some people say passing a kidney stone is like giving birth.
Others don't even know they have a stone until it passes. Either way, a kidney stone it is no laughing matter. Kidney stones are a crystallization of substances in the urine, said Dr. Pamela Fall, nephrologist at the Medical College of Georgia. The stone often becomes lodged in the ureter, a tube between the kidney and the bladder. These stones can range from a millimeter to a half-inch or more.