Kidney stones are hard deposits made of mineral and salt that form inside your kidneys. Kidney stones have many causes and can affect any part of your urinary tract-from your kidneys to your bladder. Often, stones form when the urine becomes concentrated, allowing minerals to crystallize and stick together. Passing kidney stones can be quiet painful, but the stones usually cause no permanent damage if they're recognized in a timely fashion. Depending on your situation, you may need nothing more that to take pain medication and drink lots of water to pass a kidney stone. In other instance for example, if a stone becomes lodged in the urinary tract, are associated with a urinary infection or cause complication, surgery may be needed. Your doctor may recommend preventing treatment to reduce your risk of recurrent kidney stones if you're at increased risk of developing them again.