A diagnosis of bladder stones in dogs, instead of just a UTI, may come as a bit of a surprise. To help worried dog parents process what is going on with their dear companion, integrative veterinarian Dr. Julie Buzby explains the causes, symptoms, types, diagnosis, treatment, and prevention of bladder stones in dogs.
As a dog parent, it is important to keep an eye on what happens during your dog’s potty breaks. Symptoms such as straining to urinate, urinating frequently, and having accidents in the house can all point to problems with the urinary tract.
It is easy to associate abnormal urination with a simple urinary tract infection, and this is true in many cases. However, for some dogs, the culprit is something else—bladder stones.
What are bladder stones in dogs?
Bladder stones in dogs are hard mineral conglomerations that form inside the urinary bladder. They are part of a larger category called uroliths, which are rock-like formations of minerals in the urinary tract. Dogs can develop uroliths in the upper urinary tract (the kidneys and ureters) as well as the lower urinary tract (the urinary bladder and urethra). But given the larger amount of space inside the bladder, it makes sense that 97% of uroliths in dogs develop in the bladder.
Bladder stones in dogs can vary in size (grains of sand to several inches in diameter), shape (round to irregularly shaped), outer texture (rough or smooth), and number (one or hundreds). They are understandably irritating to the bladder and can also take up a significant amount of room in some cases. Occasionally, bladder stones can even block urine from flowing down the urethra. When that happens, it is an emergency situation.
What are the signs of bladder stones in dogs?
Many dogs with bladder stones can start out asymptomatic, especially if the stones are very small. You may start to notice symptoms when the stone is larger, if there are numerous stones, or if there is a different issue, like a urinary tract infection. (Stones can predispose dogs to UTIs and vice versa.)
Symptoms associated with dog bladder stones include:
- Hematuria (blood in urine)—If your dog urinates on snow, the concrete, or inside your house, you may notice the urine is a pinkish red or contains blood clots.
- Dysuria (painful or uncomfortable urination)—Your dog may act painful when urinating or urinate and then turn around and lick the vulva or prepuce.
- Pollakiuria (frequently urinating in small amounts)—Instead of standing there and getting most of the urine out, your dog might be posturing to urinate many times and only passing a small amount of urine each time.
- Stranguria (straining to urinate)—Your dog might look like he or she is trying harder than usual to squeeze out the urine. (If your dog is straining and no urine is coming out or only a few dribbles, this could be a sign of an obstruction, which is an emergency.)
- Periuria (urinating in abnormal places)—Your normally housetrained dog may be urinating by the door, on the carpet, or in other locations in the house.
- Urinary incontinence in dogs—Sometimes your dog may be leaking urine unconsciously, especially while sleeping.
If you are seeing these signs of bladder stones, it is best to make an appointment with your veterinarian.
What are the symptoms of a urinary obstruction due to a bladder stone?
Because female dogs have shorter, wider urethras, they are less prone to obstructions from bladder stones. However, larger or more jagged stones could occasionally lodge in their urethra. On the other hand, male dogs have longer, narrower urethras. This increases the risk of a life-threatening obstruction.
Symptoms of bladder stones that are causing a urinary obstruction include:
- Inability to urinate or only dripping urine while straining—A dog with a bladder stone blocking the urethra may try to urinate over and over but be unable to get urine out or pass a few drops.
- Vomiting—Since urine is trapped in the bladder, toxins may build up in the bloodstream. This can make the dog nauseous or cause him or her to vomit. The dog may also stop eating.
- Being a lethargic dog—Due to the buildup of toxins, plus nausea and discomfort, the dog may act depressed or lethargic.
- Abdominal pain—As the bladder continues to distend, it can become very painful. Eventually, the bladder may rupture if the obstruction isn’t relieved.
- Heart arrhythmias—Electrolyte disturbances from the obstruction can lead to arrhythmias or collapse.
If you suspect your dog could have a urinary obstruction, make an emergency vet visit immediately. Urinary obstructions can lead to bladder rupture or even be fatal if left untreated.
What causes bladder stones in dogs?
So how do dogs get bladder stones to begin with? Well, uroliths form in the same manner as rocks. Given the right conditions, minerals that are present in liquid (urine in this case) can solidify into crystals. Then those crystals join together and form solid stones. In the bladder, there is usually a prolonged period of supersaturation of these minerals, leading to crystal formation.
Aside from favorable mineral concentrations in the bladder, other factors that can increase the chances of bladder stones forming include:
- Urine pH—Urine that is too acidic or alkaline can make it more likely for uroliths to form.
- Lack of inhibitors—Glycosaminoglycans and other molecules in the bladder may help prevent stones from forming. Too few of these inhibitors could be problematic.
- Dietary factors—The amount and type of minerals in the diet, protein levels of the food, and increased consumption of certain foods can influence urolith development.
- Genetic defects—Genetic mutations may cause a higher-than-normal amount of certain “stone ingredients”, like uric acid or cystine, to be in the urine.
- Low water intake—When dogs don’t drink as much water, their urine is more concentrated, which favors the creation of uroliths.
- Bladder infections—It is easier for stones to form when there is something to cling to. Foreign material, like bacteria, can serve as the foundation for crystals to form stones.
Note: These are some general contributing factors. However, they can vary from one stone type to another. Thus, the information below includes a more specific discussion of the causes of each type of bladder stone.
What are the types of bladder stones in dogs?
Six main types of bladder stones occur in dogs. Plus, there is a bonus seventh type that veterinary researchers have recently identified.
1. Struvite bladder stones in dogs
Struvites are among the two most common types of bladder stones in dogs. (The other is calcium oxalate.) They are usually rounded and smooth, but they can vary in size and number. Some of the largest bladder stones ever documented were struvite stones! Dogs with struvite stones can have a solitary large bladder stone. Or they can have dozens (if not hundreds) of tiny ones.
Struvite stones are made up of magnesium and ammonium phosphate, and they are almost always caused by the presence of a UTI in dogs. (Rarely, dogs will have sterile struvite stones. These are much more likely in cats.) Here’s how UTI-associated struvite bladder stones form.
When the body breaks down dietary protein, it leaves behind nitrogenous waste products. Most of these waste products leave the body through the urine in a form called urea. However, when certain types of bacteria are present in the bladder, as is the case with some UTIs, they create an enzyme (urease) that splits urea into ammonium and bicarbonate.
The ammonium binds with magnesium and phosphate to form struvite crystals. And the bicarbonate increases urine pH, making it harder for the crystals to dissolve again. When the crystals and bacteria stick together, the end result is a struvite stone. The formation of struvite stones can occur in as little as two weeks after the UTI starts.
2. Calcium oxalate bladder stones in dogs
Calcium oxalates are the other most common type of bladder stone in dogs. They form when there are high levels of calcium and/or oxalates in the urine. This can occur for several reasons:
- Hypercalcemia in dogs—Cancer, kidney failure in dogs, or other causes of elevated blood calcium can also lead to elevated calcium in the urine.
- Diet—Foods that are low in protein and moisture are more likely to increase oxalate formation. The same is true for diets high in carbohydrates or containing sweet potato, potatoes, and spinach.
- Endocrine disorders—Cushing’s disease in dogs (excessive production of the steroid cortisol) and primary hyperparathyroidism (the body makes too much PTH, a hormone that raises blood calcium) are the most common causes of high calcium in urine.
- Genetics—Certain dog breeds have a higher risk of developing calcium oxalate stones, including English Bulldogs, Bull Terriers, Boston Terriers, Rottweilers, American Staffordshire Terriers, and Havanese.
- Changes in gut bacteria—Having lower amounts of the bacterium Oxalobacter formigenes in the intestinal tract, which breaks down oxalate, can potentially increase oxalate levels in the blood and urine.
There are two types of calcium oxalate stones—calcium oxalate monohydrate and calcium oxalate dihydrate. The monohydrate variety makes for a smooth stone, while the dihydrate stones are pointy and jagged. Both form in acidic to neutral urine.
3. Urate bladder stones in dogs
Uric acid in its various forms, most commonly ammonium urate (86% of the time), makes up urate stones. This type of stone tends to form for one of two reasons: liver disease or genetics.
Urate crystals can be associated with liver disease in dogs. When dogs develop liver disorders such as cirrhosis, microvascular dysplasia, or portosystemic shunts (PSS), their ability to convert uric acid into a more soluble form decreases. Similarly, it becomes harder to convert ammonia to urea, making urine more acidic. This creates a favorable environment for urate crystals and then stones to form from uric acid.
Genetics can also play a role in urate stone development. The following breeds may have a genetic defect that causes them to have increased levels of uric acid in their blood and urine. This can contribute to the formation of urate stones.
- Dalmatians
- English Bulldogs
- French Bulldogs
- Australian Shepherds
4. Cystine bladder stones in dogs
Cystine crystals and stones can form in neutral to mildly acidic urine. They will form when there is too much cystine present in the urinary bladder, usually due to diet or a genetic defect. Diets that are high in taurine and carnitine can increase the risk of cystine stone formation.
Some dog breeds may also have a genetic defect where the kidneys cannot effectively reabsorb cystine. It accumulates in urine and forms stones. Male dogs are much more likely to develop cystine stones compared to female dogs.
Dog breeds with a higher risk of developing cystine stones include the following:
- Newfoundlands
- Labrador Retrievers
- Mastiffs (Bullmastiffs, English)
- Rottweilers
- Scottish Terriers
- Bulldogs (American, French, English)
- Miniature Pinschers
- Dachshunds
- Chihuahuas
5) Calcium phosphate bladder stones in dogs
Calcium phosphate stones most commonly occur in dogs with primary hyperparathyroidism and Cushing’s disease. But they can also form when dogs have high levels of calcium in their urine for other reasons. Additional factors that promote the formation of calcium phosphate bladder stones include alkaline urine, as well as a lower amount of crystallization inhibitors. This makes it easier for calcium phosphate crystals to form stones.
Compared to other types of bladder stones, calcium phosphates only account for 2% of all uroliths. However, some struvite or calcium oxalate stones may also have a calcium phosphate component. (Bladder stones can have a mixed composition and are named for the mineral that makes up the majority of the stone. Thus, a stone that is primarily struvite with a smaller amount of calcium phosphate would be classified as a struvite.)
6. Xanthine bladder stones in dogs
Xanthine stones account for less than 1% of all uroliths in dogs. They most commonly form when dogs take a specific medication (allopurinol) without proper dietary restrictions. However, there is also a genetic mutation that may predispose some breeds to xanthine stones.
Vets may prescribe allopurinol for dogs who develop urate stones or have leishmaniasis, a serious parasitic disease. If dietary purines (such as those from organ meats or seafood) are not limited, dogs taking allopurinol may develop xanthine stones. There are specific veterinary prescription diets that are purine-limited to help avoid this issue.
Certain small-breed dogs may have an increased risk of xanthine stone formation due to a recessive mutation. These breeds include:
- English Cocker Spaniels
- Cavalier King Charles Spaniels
- Dachshunds
- Toy Manchester Terriers
- English Toy Terriers
7. A new type of bladder stone—calcium tartrate tetrahydrate
In April 2025, researchers at the College of Veterinary Medicine at the University of Minnesota published a paper entitled Association of Diet and Calcium Tartrate Tetrahydrate Uroliths in Dogs. It provided information on the new type of bladder stone identified by the Minnesota Urolith Center—the calcium tartrate tetrahydrate (CTT) urolith.
This particular stone requires a source of tartaric acid. In this paper, 25 of the 33 dogs whose owners provided information about diet, supplements, and medication, a source of tartaric acid was found. And in 24 of those 25 cases, the source of the tartaric acid was a compound called choline bitartrate.
Several supplements and diets containing choline bitartrate were implicated in the study. Based on these findings, the investigators suggest that veterinarians should consider if the dog is on a medication, diet, or supplement containing tartaric acid (most likely as choline bitartrate) if calcium tartrate tetrahydrate stones are found.
How will the vet diagnose a dog with bladder stones?
If your dog has symptoms that suggest a UTI or bladder stones, your vet will start with a comprehensive physical exam. Sometimes the vet may be able to palpate large or numerous stones in the bladder. However, just because the vet can’t feel them doesn’t mean they aren’t there.
Next the vet may recommend some diagnostic testing, including:
Urinalysis with microscopic examination
The vet will use a urine reagent strip to assess the pH and levels of protein, bilirubin, blood, and other chemicals in the urine. Additionally, the vet will measure the specific gravity (concentration) of the urine and describe what the urine looks like overall. Then he or she will examine the urine sediment for red blood cells, white blood cells, bacteria, crystals, and bladder cells.
Dogs with bladder stones sometimes have crystals in their urine. However, plenty of dogs have crystals in the urine without having bladder stones. And not all dogs with bladder stones have crystals in their urine. (Interestingly, 50% of urine samples from healthy dogs can contain struvite crystals. This is especially likely if the sample sits at room temperature for more than an hour.)
The type of crystals present in the urine can offer clues as to what a bladder stone is made of. Plus, the overall pH of the urine can help, too. Stones tend to have a pH at which they most commonly form.
Urine and/or stone culture and sensitivity
If the urinalysis points toward a urinary tract infection in addition to bladder stones, the vet may submit urine for a culture and sensitivity. This identifies the organism causing the infection and shows which antibiotics should and should not be effective. Sometimes the vet will also send some stones in for culture because bacteria may get trapped within the stones. This could lead to a negative urine culture but a positive stone culture.
Note: To get accurate results from the culture, the vet will use a needle to draw a sample of urine straight from the bladder. “Free catch” samples obtained when the dog urinates have too much contamination.
Imaging (X-ray and/or ultrasound)
X-rays can be great for evaluating the size, shape, and number of stones present. Plus, they allow the vet to look for stones in the urethra. Struvite, calcium oxalate, and calcium phosphate stones are easily detected on X-rays. However, xanthine, cystine, and urate stones appear very faint on X-rays and can be easy to miss. It is also important to keep in mind that X-rays may not be able to find uroliths smaller than 3 mm.
Performing a bladder ultrasound allows the vet to visualize all stone types. Additionally, the ultrasound helps the vet to look for bladder cancer in dogs or other abnormalities. However, it is not as accurate as X-rays when it comes to counting stones and evaluating their shape.
Blood tests
Blood tests for dogs can’t find bladder stones. However, they can reveal problems that cause bladder stones or are the result of a urinary obstruction.
If the dog has urate stones, the vet may want to run a bile acid test to screen for liver dysfunction. And bloodwork may reveal elevated blood calcium in dogs with kidney disease, Cushing’s disease, or hyperparathyroidism. Plus, dogs with urinary obstructions will have elevated kidney values and abnormal electrolytes.
Stone analysis
Vets can submit bladder stones to the Minnesota Urolith Center for stone analysis. Based on the composition of the stone, the vet can make recommendations for (hopefully) preventing the formation of more bladder stones.
What is the treatment for bladder stones in dogs?
The treatment plan the vet devises for your dog’s bladder stones depends on the number, size, shape, and type of stones the dog appears to have. Plus, the vet will take into account the severity of your dog’s symptoms and whether or not the stones are blocking the urethra (which is an emergency).
With struvite, urate, and cystine stones, dissolving them using a special food may be an option. However, stones like calcium oxalates, calcium phosphates, and xanthines, plus any stones causing urethral obstruction or significant symptoms, require prompt surgical removal.
Dissolving the stones with a special prescription diet
Veterinary prescription diets are available that can help dissolve struvite, urate, and cystine bladder stones. Plus, prescription diets can help prevent, but NOT dissolve, calcium oxalate stones. (Note: While there are over-the-counter urinary diets as well, they are not equivalent to veterinary prescription urinary diets.)
Struvite stones (composed of magnesium and ammonium phosphate) tend to form in alkaline urine. Thus, diets that acidify urine and decrease magnesium and phosphorus levels in the urine will be helpful.
For urates and cystines, which form in acidic urine, your vet will choose a urinary diet that alkalinizes urine and decreases levels of uric acid and cystine in the urine. All urinary diets promote urine dilution as well. This decreases the chances of minerals in the urine forming crystals and then stones.
With dissolution diets, it may take 10 to 14 days of treatment before seeing any improvement in clinical signs. Depending on the size of the stone(s), it could be several weeks or months before the stones have dissolved completely. To make sure treatment is working, your vet may repeat imaging and recheck a urine sample every 2-4 weeks. If there is no improvement, the stones may require surgical removal instead.
During the dissolution period, dogs with struvite stones need antibiotic therapy too
Struvite bladder stones usually form secondary to a UTI and may incorporate some bacteria into the stone. As the stone dissolves, it will release bacteria that were trapped in the center, increasing the risk of re-infection and new bladder stones forming. Thus, it is crucial for dogs with struvite stones to also stay on antibiotics for the duration of the dissolution period. (However, in the rare case of sterile struvite stones, antibiotics may not be needed.)
For cystine and urate stones, bacteria don’t typically play a significant role. As a result, the dog may not need antibiotics unless he or she also has a UTI.
Ensure your dog only eats the prescription dissolution diet and nothing else
In order for the dissolution diet to be effective, it is important that your dog eats only that diet. Giving your dog treats or other types of dog food can negate the prescription diet’s ability to alter the pH and mineral content of the urine. As a result, the stones may not dissolve as expected.
Surgically removing the bladder stones
Regardless of stone type, your veterinarian may recommend surgical removal in any of the following scenarios:
- The stone is not dissolving with diet (and antibiotics if needed)
- Diet cannot dissolve that type of stone
- The dog has a partial or complete urinary obstruction due to the stone
- The stone is causing significant enough discomfort that waiting until it dissolves may not be in the best interest of the dog
Most commonly, the veterinarian will perform a cystotomy to remove the stone(s). This involves cutting directly into the urinary bladder itself, removing the stones, and suturing the bladder back together again.
In veterinary medicine, we say that the urinary bladder is one of the most “forgiving” organs because it heals so well on its own. This is good news for dogs who need cystotomies!
If bladder stones are stuck in the urethra, it may be possible to flush them back into the bladder for removal through the cystotomy incision. This is called retrograde urohydropropulsion. However, sometimes the stones are lodged so firmly in the urethra that the surgeon cannot push them back into the bladder. In that case, he or she may need to make an incision into the urethra to remove the stone instead.
Occasionally, in male dogs, the vet may make a new permanent opening in the urethra (urethrostomy). Generally, he or she will reserve this procedure for situations where there is concern about poor healing of the urethra and/or re-obstruction in the future.
Voiding urohydropropulsion to remove stones without surgery
A minimally invasive technique called voiding urohydropulsion is sometimes successful in removing small bladder stones without the need for surgery. It does, however, require sedation or sometimes anesthesia.
During the procedure, the vet will distend the bladder with saline. Then he or she positions the dog, allowing gravity to cause the stones to settle where the urethra meets the bladder. Finally, the vet manually expresses the dog’s bladder. The stream of saline will carry small bladder stones with it, allowing the dog to “urinate out” the stones.
However, it is important to note that this procedure typically only works for dogs weighing more than 16 pounds and for stones less than 5 mm in size. It also isn’t intended for dogs with a urethral obstruction.
Lithotripsy to break down bladder stones
A procedure called lithotripsy, which is performed at specialty hospitals, may be an option for some dogs with bladder stones. It can be performed in two different ways.
Laser lithotripsy
Laser lithotripsy involves using a special laser to break the uroliths into smaller pieces that can be passed on their own or removed using the cystoscopy (bladder scope) basket or voiding urohydropropulsion.
Anesthesia is necessary for laser lithotripsy as it is performed by passing the scope and lithotripter into the urethra and bladder. This procedure is 83-96% effective in female dogs due to their shorter and wider urethras. But it is only 68-81% effective for male dogs. Plus, it isn’t suitable for small dogs (especially males), larger stones, or dogs with numerous stones.
Extracorporeal shock wave lithotripsy
Another type of lithotripsy, extracorporeal shock wave lithotripsy, involves the use of shock waves from outside of the body to help break up bladder stones.
The dog is typically anesthetized or sedated for this procedure as well. Extracorporeal shock wave lithotripsy is great for stationary stones such as kidney stones. But it is less effective for movable stones like bladder stones. It also doesn’t work well for all stone types.
Can dogs pass bladder stones on their own?
In rare cases, dogs may be able to pass stones on their own with no intervention. This is more common for female dogs than male dogs. Plus, the stones need to be very small in order for this to happen.
However, being able to pass some small stones doesn’t guarantee the dog can or will pass all the stones in the bladder. Additionally, there is the risk that a stone could get lodged in the urethra, causing a urinary obstruction. For these reasons, treatment for bladder stones, not waiting to see if the dog naturally passes the stones, generally is the best option.
Are there home remedies for bladder stones in dogs?
There are no home remedies for the dissolution and removal of bladder stones in dogs. However, there are steps that dog parents can take at home to help their dog during stone dissolution and decrease the risk of future bladder stones.
1. Work with your vet to find the right diet for a dog who has bladder stones.
Nutrition can play a significant role in treating and preventing some, but not all types of bladder stones. Since the various stones form from different minerals and at different pHs, the veterinary prescription diets for stone dissolution and/or prevention are not one-size-fits-all.
Instead, there are several different options for prescription urinary diets. Each is targeted toward a few specific types of stones. Thus, it is important to follow your veterinarian’s advice regarding whether your dog would benefit from a prescription urinary diet, and which one is best for your dog’s condition.
2. If your dog is on a prescription urinary diet, don’t give him or her other foods, too.
If your dog is eating a prescription diet intended to dissolve and/or prevent bladder stones, it is essential to feed that food and only that food, as discussed earlier. These diets work by controlling the dog’s intake of certain minerals or nutrients and altering the pH of the urine. Giving your dog other types of dog food, treats, or even some vegetables or meats may increase the levels of those minerals or alter the urine pH, both of which may keep the diet from working well.
3. Increase your dog’s water intake.
Regardless of whether your dog ends up needing a prescription diet or not, dogs who are prone to bladder stones definitely benefit from drinking more water. Increased water intake translates to more dilute urine. This makes it harder for the minerals to “find each other” to form crystals and stones.
You can influence how much water your dog drinks by changing the water in the bowl frequently, ensuring he or she always has access to fresh, clean water, and using a water fountain or elevated dish.
Changing to canned food or adding water to dry food are other easy ways to increase how much fluid your dog consumes.
4. Follow your vet’s recommendations for preventing future bladder stones.
In addition to feeding your dog a bladder stone-prevention diet (for some stones) and increasing water intake, there may also be additional steps you can take to decrease the chances of stones recurring. This typically depends on the type of stone present.
If your dog had calcium oxalate stones, the vet may recommend avoiding high glycine treats (pig’s ear, rawhides, jerky, etc.) and high oxalate foods such as potatoes, sweet potatoes, and spinach. The vet may also prescribe diuretics or urinary alkalinizing agents like potassium citrate to help prevent calcium oxalate stones.
If your dog is prone to struvite stones, which usually form as a result of a UTI, the focus will be on preventing and detecting UTIs. Taking your dog out frequently so urine doesn’t sit in the bladder for a long time and increasing water intake are great UTI prevention strategies. Plus, closely monitoring your dog for signs of a UTI and getting him or her to the vet quickly can help get the infection under control as soon as possible.
Calcium oxalate stones and struvite stones are the most common, so they are the ones I’m sharing here. However, there are tips and considerations specific to the other types of stones, too. Your vet can advise you about what is best for your dog’s particular situation.
Is the recurrence of bladder stones in dogs likely?
It varies from stone to stone and dog to dog, but in general, dogs who are prone to bladder stones are at risk for forming stones again. For example, approximately 35% of dogs will have calcium oxalate stones again within one year of the first occurrence, and this number increases to almost 50% by three years.
Additionally, stones such as urates or cystines that occur as a result of a genetic defect also have a high chance of coming back. Plus, if a dog is prone to UTIs, this increases the chances he or she could develop struvite stones again.
For most bladder stones, recurrence is especially likely if you don’t take preventive measures or if your dog has an underlying problem that promotes stone formation. However, sometimes stones may form again even if you try to do everything right.
Your veterinarian can tell you what to expect with your dog’s particular type of stone and how to minimize the chances of more stones forming. He or she may recommend special diets, medications, routine monitoring, or other interventions. Although many types of stones can recur, it is still worth doing what you can to prevent them or at least slow down their formation.
Work with your vet to address your dog’s bladder stones
Finding out your dog has bladder stones can be stressful. Suddenly, you are facing decisions about surgical removal, dissolution diets, or other interventions when you might have only imagined coming home with some antibiotics for a UTI. As long as your dog doesn’t have a urinary obstruction, which is an emergency, it is ok to take some time to talk the options over with your vet and do some research.
Treating bladder stones isn’t nearly as simple as treating a UTI. But having a stone-free bladder can bring your dog significant relief from his or her symptoms. With the support of your veterinarian, family, the information in this article, and some snuggles from your dog, you can feel calmer and more confident as you navigate bladder stones with your precious pup.
What kind of bladder stones did your dog have?
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