here's a great webmd overview on kidney stones for you. basically kidney stones are formed when minerals normally found in urine stick together forming hard pebbles. sometimes people eliminate these stones when they urinate (pee). other times the stones are so large -- or there are so many -- that a medical treatment is required to get rid of them. you can help yourself avoid getting kidney stones by drinking plenty of water. your urine should usually be clear to light-yellow in color. if your urine is dark it could be an indication you're not drinking enough water. hope this helps!
what causes kidney stones?