Kidney stones are usually small, but they can grow to be as big as a golf ball. They’re formed when certain minerals and salts in your urine become concentrated and crystallize.

There are four main types of kidney stones:

• Calcium oxalate stones: These are the most common type of kidney stone. They’re formed when calcium and oxalate, a substance found in many foods, combine in your urine.
• Uric acid stones: These stones are more common in people who have gout or who eat a lot of meat. They’re formed when uric acid, a waste product of your body, becomes concentrated in your urine.
• Struvite stones: These stones are more common in women and people who have had urinary tract infections. They’re formed when ammonia, a waste product of bacteria, combines with magnesium and phosphate in your urine.
• Cystine stones: These stones are rare and are caused by a genetic condition that makes your kidneys leak too much cystine, an amino acid, into your urine.

Symptoms of kidney stones can include:

• Severe pain in your side or back, below your ribs
• Pain that radiates to your groin or lower abdomen
• Blood in your urine
• Nausea and vomiting
• Fever and chills
• Difficulty urinating or urinating more often than usual

If you think you might have a kidney stone, it’s important to see a doctor right away. They can diagnose the condition and recommend treatment.

Treatment for kidney stones depends on the size and location of the stone. Small stones may pass on their own with pain medication and plenty of fluids. Larger stones may need to be treated with surgery or other procedures.

Prevention of kidney stones includes:

• Drinking plenty of fluids, especially water
• Eating a healthy diet that’s low in salt and animal protein
• Getting regular exercise