A Plain-Language Guide to Recognizing, Treating, and Preventing Kidney Stones
Credit: Daily Vitality
It often starts without much warning — a sudden, gripping pain low in your back or side, just beneath the ribs and usually on one side. The ache can roll in waves, spread toward your lower belly and groin, and make it almost impossible to sit still or find a position that brings relief. For a lot of people, it ranks among the most intense pain they've ever felt.
If that sounds familiar, there's a good chance you're dealing with a kidney stone — and the reassuring part is that stones are very common and highly treatable. Most small ones pass on their own with time, fluids, and pain relief, while larger stones have well-established options to clear them. This guide walks through what kidney stones are, how to recognize them, how they're diagnosed and treated, and the everyday steps that help keep them from coming back.
A kidney stone is a small, hard deposit of minerals and salts that forms inside one or both kidneys — which is why you might see it written on a medical report as renal calculi or nephrolithiasis. As the National Institute of Diabetes and Digestive and Kidney Diseases explains, stones tend to form when urine becomes concentrated and minerals such as calcium, oxalate, and uric acid build up faster than the fluid can dilute them. When that happens, those minerals can crystallize, cling together, and slowly grow into a solid, pebble-like stone.
Here's the part that catches many people off guard: a stone can sit quietly in your kidney for a long time and cause no trouble at all. The pain usually begins only when it starts to move and slips into a ureter, the narrow tube that carries urine from each kidney to the bladder. If the stone lodges there and blocks the flow, the kidney swells and the ureter spasms — and that's the moment the now-famous pain shows up.
You're also in very large company. Kidney stones are common, affecting roughly one in ten people at some point in their lives, and the National Kidney Foundation notes that they account for more than half a million emergency room visits in the United States each year. Knowing what you're dealing with — and what your options are — takes a lot of the fear out of the experience.
The hallmark of a kidney stone is sudden, sharp pain in your side and back, just below the ribs and typically on one side. Mayo Clinic describes how that pain often radiates down toward the lower abdomen and groin, arrives in waves, and changes in intensity as the stone shifts position. Many people describe it as relentless — the kind of pain that makes it hard to stay still or get comfortable in any position.
Pain isn't the only clue, though. A stone can announce itself through several other symptoms as it travels:
That last pairing — fever and chills — stands apart from the others. While the rest are uncomfortable but expected, fever can point to an infection developing alongside the stone, and that changes the picture from "painful" to "potentially urgent." We'll come back to exactly when that's an emergency a little later on.
Not every stone is made of the same material, and the type genuinely matters, because it shapes both why a stone formed and how you might prevent the next one. About 80% of stones are calcium stones, most often built from calcium oxalate and, less commonly, calcium phosphate. The remaining types are less frequent but worth understanding.
Calcium stones are by far the most common. Oxalate is a substance your body makes on its own and also absorbs from certain foods, and when there's more of it (or more calcium) in your urine than the fluid can handle, calcium oxalate stones can form.
Uric acid stones tend to show up in people who lose a lot of fluid through chronic diarrhea, who eat a diet heavy in animal protein, or who live with conditions like diabetes, metabolic syndrome, or gout. Interestingly, this is the one type that can sometimes be dissolved with medication that makes the urine less acidic.
Struvite stones form in response to a urinary tract infection. They can grow quickly and become quite large — sometimes filling much of the kidney as a branching "staghorn" stone — occasionally with little warning.
Cystine stones are rare and run in families. They occur in people with an inherited condition called cystinuria, which causes the kidneys to leak too much of an amino acid called cystine into the urine.
Kidney stones rarely come down to a single cause. More often, several factors line up at once. The most important — and the most changeable — is simply not drinking enough fluid, because dehydration leaves urine concentrated and gives crystals the perfect environment to form and clump together.
Beyond hydration, Mayo Clinic and other major sources point to a familiar set of contributors:
Understanding which of these apply to you is the first step toward a prevention plan that actually fits your life, rather than a generic checklist.
If a stone is suspected, the goal is to confirm it's really a stone — and to rule out other causes of the pain. That usually starts with a conversation about your symptoms and a physical exam, followed by a few straightforward tests.
A urinalysis checks your urine for blood, crystals, and signs of infection, while blood tests look at how your kidneys are working and measure minerals like calcium and uric acid. Imaging is what pins down the stone itself. A non-contrast CT scan is the most accurate option and is considered the gold standard, since it shows a stone's exact size and location. Ultrasound, which uses no radiation, is another common choice — especially during pregnancy — though it's less precise at spotting very small stones.
If you've had more than one stone, your care team may suggest catching a stone as it passes (often by straining your urine) so a lab can identify its type. They may also recommend a 24-hour urine collection to uncover the specific metabolic factors driving your stones, which makes any prevention plan far more targeted.
This is the question almost everyone asks first, and the honest answer is that it depends on two things: the stone's size and its location in the urinary tract. Size tells most of the story, but a small stone in a tight spot can still cause a big obstruction, so the numbers below are general guideposts rather than guarantees.
The Urology Care Foundation notes that smaller stones are much more likely to pass without intervention than larger ones. When a stone does pass, it can take anywhere from a few days to a few weeks. If several weeks go by without success, or your symptoms get worse — particularly with signs of infection or a persistent blockage — that's typically the point where a clinician reassesses and may suggest a more active approach.
Treatment really falls into two camps: helping a small stone pass at home, and clearing a larger or stuck stone with a procedure. The right path depends on the stone's size, location, and composition, along with your overall health.
When a stone looks small enough to pass on its own, the usual approach centers on comfort and patience. That often means drinking plenty of fluids, managing pain (frequently with anti-inflammatory medicines like ibuprofen when appropriate), and giving the stone time to make its journey.
Some people are also offered what's called medical expulsive therapy — an alpha-blocker such as tamsulosin that relaxes the ureter so the stone can pass more easily and with less discomfort. The American Urological Association strongly supports this option for ureteral stones 10 mm or smaller, typically for about a month. Catching the stone when it finally passes is useful too, since analyzing it helps shape your prevention plan.
When a stone is too large to pass, won't budge, or is causing ongoing problems, several well-established procedures can clear it:
There's one scenario that moves to the front of the line. If a stone completely blocks urine flow and infection sets in, the infection can become trapped behind the blockage and turn serious very quickly. In that situation, the priority is urgent drainage of the kidney — usually with a ureteral stent or a small nephrostomy tube — along with antibiotics, before the stone itself is treated.
Prevention is where you have the most influence, and it's worth the effort: without specific steps, about half of people who form one stone will form another within five to ten years. The encouraging news is that the most effective measures are also the most accessible.
Hydration tops the list. Guidance from the NIDDK's dietary recommendations centers on drinking enough fluid to produce roughly 2 to 2.5 liters of urine a day, which usually means a higher total fluid intake — and more still in hot weather or with heavy sweating. Diet plays a supporting role too: easing back on sodium lowers the amount of calcium your kidneys push into urine, keeping animal protein portions moderate can help, and limiting sugar-sweetened drinks is often suggested.
A simple at-home gauge of your hydration is the color of your urine. Pale and clear generally suggests you're drinking enough; darker urine is a nudge to reach for more water.
One persistent myth is worth clearing up. If you form calcium stones, it's tempting to assume you should cut calcium from your diet — but the National Kidney Foundation points out that getting the recommended amount of calcium from food actually helps, because calcium binds oxalate in the gut and keeps it from being absorbed. Cutting dietary calcium can backfire. Decisions about calcium supplements, on the other hand, are best made one-on-one with a clinician.
Finally, depending on the type of stone you tend to form, a healthcare professional may discuss medications that lower your risk — for example, a thiazide diuretic or potassium citrate for some calcium stones, potassium citrate and sometimes allopurinol for uric acid stones, or steps to clear the infection behind struvite stones. These are always tailored to the individual and monitored over time.
Most stones are uncomfortable rather than dangerous, but certain signs mean it's time to get checked promptly rather than wait things out. It's worth seeking care if you notice:
Pain combined with fever and chills can mean an infection is developing alongside a blocked stone. This is a medical emergency — infection trapped behind a blockage can spread to the bloodstream and become life-threatening, so it calls for immediate medical attention rather than waiting to see if the stone passes.
Left unaddressed, stones can lead to uncontrolled pain, urinary infections that spread to the kidneys, a lasting blockage that makes the kidney swell, and — over time — possible kidney damage. None of that is meant to alarm you; it's simply why timely care and a prevention plan are so worthwhile.
This article is for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare professional with any questions about a medical condition or before starting or changing any treatment.
About the Author
Angela Nightingale is a Senior Editor at Daily Vitality with over two decades of experience in digital publishing and health and wellness content. She specializes in turning complex, often-confusing health topics into clear, calm, and practical guidance that respects the reader's intelligence. Her work focuses on helping people feel informed and confident — never overwhelmed or alarmed — as they make everyday decisions about how they eat, move, rest, and age.
It varies, but passing a small stone usually takes anywhere from a few days to a few weeks. If several weeks pass without success, or your symptoms worsen, it's worth checking back in with a clinician.
Size and location both matter, but as a general guide, stones smaller than about 5 mm often pass on their own — roughly eight or nine times out of ten. Stones between 5 and 10 mm pass less reliably, and those larger than about 10 mm usually need a procedure.
Most people describe sudden, severe pain in one side of the back or belly, just below the ribs. It often comes in waves, can spread toward the lower abdomen and groin, and tends to make it very hard to find a comfortable position.
They can be. Pain accompanied by fever and chills may signal an infection behind a blocked stone, which is a medical emergency. Severe pain with vomiting, blood in the urine, or trouble passing urine also warrants prompt medical attention.
Yes — staying well hydrated is the single most effective way to lower your risk of forming stones, because it keeps urine diluted so minerals are less likely to crystallize. Many guidelines point to drinking enough to produce roughly 2 to 2.5 liters of urine a day.
Generally no. Getting the recommended amount of calcium from food actually helps lower the risk of calcium oxalate stones, because calcium binds oxalate in the gut. Cutting dietary calcium can make matters worse, though calcium supplements are a separate question best discussed with a clinician.
They often do. Without specific preventive steps, about half of people who have one stone form another within five to ten years, which is why hydration, diet, and follow-up testing matter so much.
Calcium stones, which make up about 80% of cases and are usually made of calcium oxalate. Other types include uric acid, struvite (linked to infections), and rare inherited cystine stones.
Diets high in sodium, heavy in animal protein, or rich in sugar-sweetened beverages are associated with higher stone risk for some people. Moderation, rather than strict elimination, is the usual theme.
