Close Window
Library Search Go Advanced Search
Español (Inicio)


Kidney Stones

Your kidneys are the chemical filters for your body. These bean-shaped organs constantly screen your blood, removing wastes and excess fluids. Healthy kidneys maintain the chemical balance your body needs.

What Are Kidney Stones?

Kidney stones are made up of chemical crystals that separate out from urine. These crystals clump together to make “stones.” They form in the calix of the kidney. They may stay in the kidney or move into the urinary tract. 

Why Kidney Stones Form

Kidneys form stones for many reasons. If you don’t drink enough fluid, for instance, you won’t have enough urine to dilute chemicals. Then the chemicals may form crystals, which can develop into stones.

Risk Factors:

  • Fluid loss (dehydration) can concentrate urine, causing stones to form.  It is recommended to drink at least two quarts daily.

  • Certain foods contain large amounts of the chemicals that sometimes crystallize into stones.  A diet high in protein and low in fiber may increase the risk of developing certain types of kidney stones.

  • Kidney infections foster stones by slowing urine flow or changing the acid balance of your urine.  Disorders such as gout, chronic urinary tract infection, and hypothyroidism can increase the risk of kidney stones.

  • Family history - if relatives have had kidney stones, you're more likely to have them, too.

Where Stones Form

Stones begin in the cup-shaped part of the kidney (calix). Some stay and grow. Others move within the kidney or into the ureter. There they can lodge, block the flow of urine, and cause pain.


Many stones cause sudden and severe pain and bloody urine. Others cause nausea or frequent, burning urination. Symptoms often depend on your stone’s size and location. Fever may indicate a serious infection. Call your doctor right away if you develop a fever.

Preventing Kidney Stones

If you've had a kidney stone, you may worry that you will have another one.  Removing or passing your stone doesn't prevent future sontes.  With your healthcare provider's help though, you can reduce your risk of forming new stones.  Follow these guiedlines to help prevent forming new stones.

Drink Lots of Water:

Staying well hydrated is the best way to reduce your risk of future stones.  Drink 8-10 glasses of water daily

Take Medications if Needed:

Medications, including vitamins and minerals, may be prescribed for certain types of stones. Some medications decrease stone-forming chemicals in your blood.  Others help prevent those chemicals from crystallizing in urine.  Other help keep a normal acid balance in your urine.

Follow Your Prescribed Diet:

Your healthcare provider will tell you which foods contain the chemicals you should avoid.  Your healthcare provider may also suggest talking to a dietitian.  He or she can help you plan meals that won't put you at risk for future stones.  You may have to limit certain foods, depending upon which type of stones you've had.  The most common types of kidney stones are made from calcium and oxalate.

For Calcium Oxalate Stones:  Limit high-calcium foods and calcium or Vitamin C supplements.  Limit high-oxalate foods such as cola, tea, chocolate, and peanuts.

Food Group

High Oxalate Foods


Beer, chocolate beverage mixes, cocoa, instant tea, instant coffee

Breads and Cereals      

Grits, wheat bran, wheat germ, whole-wheat flour


Berries (blackberries, gooseberries, black raspberries, strawberries) lemon, lime, rhubarb, tangerines

Meat Substitutes

Peanut butter, nuts, tofu


Beans (wax or legume), beets, celery, spinach, eggplant, leeks, summer squash


Chocolate, cocoa, vitamin C intake in excess


For Uric Acid Stones:  Limit high purine foods such as anchovies, poultry, and organ meats.  These foods increase uric acid production.

For Cystine Stones:  Limit high methionine foods (fish is the most common).  These foods increase production of cystine.

© 2000-2017 The StayWell Company, LLC. 780 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.