The function of your kidneys is to remove excess fluid from your body and filtering out unneeded electrolytes and wastes from your blood, resulting in the production of urine.

Kidney stones form when the minerals and acid salts in your urine crystallize, stick together, and solidify into a mass. This happens when your urine contains more crystal-forming substances, such as calcium and uric acid, than the available fluid can dilute. This can happen when urine is highly acid or highly alkaline. Certain drugs can also promote kidney stones, such as Lasix (furosemide), Topomax (topiramate), and Xenical, among others. Many times, it is a combination of factors that create an environment favorable to stone formation.

The conditions allowing kidney stones to form are created by problems in the way your body absorbs and eliminates calcium and other substances. Sometimes the underlying cause is a metabolic disorder or kidney disease.

You will not experience symptoms until the stone moves into the ureter; a urine carrying tube from your kidney to your bladder. Common symptoms include:

Pain in your side and back, below your ribs
Episodes of pain lasting 20 to 60 minutes, of varying intensity
Pain ?waves? radiating from your side and back, to your lower abdomen and groin
Bloody, cloudy or foul-smelling urine
Pain with urination
Nausea and vomiting
persistent urge to urinate
Fever and chills (indicates an infection is also present)

Lifestyle modifications go a long way to help prevent this painful condition. Staying hydrated is perhaps the most important thing one can do. You should also get adequate exercise while avoiding products like sugar, soy, and processed foods.