Bladder Stones in Cats: Signs & Treatment
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Bladder stones are hard mineral deposits that form in a cat's bladder and irritate its lining. Signs include straining to urinate, blood in the urine, frequent trips to the litter box, and urinating outside it. The two most common types are struvite and calcium oxalate, and treatment differs between them — some dissolve with a special diet, while others need removal. A stone that blocks the urethra is an emergency.
When it's urgent
If a stone lodges in the urethra and blocks urine flow, it becomes a life-threatening emergency — especially in male cats. A cat straining with little or no urine, crying, vomiting or lethargic needs emergency care immediately. See our guide on urinary blockage in cats.
Most bladder stones cause chronic discomfort rather than sudden crisis, but because a stone can shift and obstruct at any time, any straining cat deserves prompt veterinary attention.
What bladder stones are
Bladder stones (uroliths) form when minerals in the urine concentrate and crystallize, then clump into stones ranging from sand-like grit to larger masses. They develop through a mix of urine chemistry, pH, hydration, diet, and sometimes infection or an underlying metabolic issue. As they roll around and rub the bladder wall, they cause the inflammation and bleeding behind the symptoms.
Stones are one cause within the broader picture of feline lower urinary tract disease, and they produce many of the same signs as cystitis or crystals — which is why testing is needed to tell them apart.
Struvite vs. calcium oxalate
The two most common stone types are managed very differently, so identifying which one your cat has is central to treatment:
| Struvite | Calcium oxalate | |
|---|---|---|
| Dissolves with diet? | Often yes, with a therapeutic diet | No — must be removed |
| Urine pH link | Tends to form in alkaline urine | Tends to form in acidic urine |
| Prevention | Diet and controlling infection | Diet, hydration, ongoing monitoring |
Because these two respond to opposite conditions, a diet aimed at one type can encourage the other — which is why prevention should always be vet-directed rather than guessed at.
Signs and diagnosis
The signs mirror other urinary problems:
- Straining or difficulty urinating
- Blood in the urine
- Frequent, small urinations and trips to the box
- Urinating outside the litter box
- Licking the genital area, and signs of pain
Your vet diagnoses stones with a urinalysis plus imaging — X-rays or ultrasound — since some stones show up on one but not the other. Analyzing a stone after removal, or the crystals in the urine, confirms the type and guides prevention.
Treatment, prevention and tracking
Treatment depends on the stone. Struvite stones can often be dissolved over several weeks with a therapeutic diet, avoiding surgery. Calcium oxalate stones can't be dissolved and are usually removed surgically or, for small ones, by non-surgical flushing techniques. Prevention centers on the right diet, plenty of water intake, and treating any infection. Because stones frequently recur, follow-up urine tests and imaging are part of long-term care. Tracking your cat's urinary signs, litter-box habits and recheck results over time helps confirm a dissolution diet is working and flags a recurrence early — a stone caught small is far easier to manage than one that grows or blocks.
Keep your cat's urinary history in one place
Tavi lets you log litter-box changes, straining and recheck results over time, so you can see whether a dissolution diet is working and catch a recurring stone early. Free for your first pet.
Frequently asked questions
Can bladder stones in cats dissolve on their own?
Some can. Struvite stones often dissolve over several weeks with a therapeutic diet, which can avoid surgery. Calcium oxalate stones cannot be dissolved and must be physically removed. That's why identifying the stone type is essential before choosing a treatment.
What are the signs of bladder stones in cats?
Common signs include straining to urinate, blood in the urine, frequent small urinations, urinating outside the litter box, and licking the genital area. These overlap with other urinary conditions, so a vet needs imaging and a urinalysis to confirm stones.
How are bladder stones in cats diagnosed?
Vets use a urinalysis along with X-rays or ultrasound, since different stones are visible on different imaging. Analyzing a passed or removed stone, or the crystals in the urine, identifies the type. That type determines whether diet or surgery is the right treatment.
What diet prevents bladder stones in cats?
There's no single answer, because struvite and calcium oxalate stones form under opposite conditions, so a diet that prevents one can encourage the other. Your vet will prescribe a therapeutic diet matched to your cat's stone type, along with increased water intake. Never choose a stone-prevention diet without veterinary guidance.
Are bladder stones in cats an emergency?
Not usually on their own, but they become an emergency if a stone lodges in the urethra and blocks urine flow, especially in male cats. A blocked cat can die within a day or two. Any cat straining with little or no urine needs immediate emergency care.
Tavi's guides are informational and not a substitute for professional veterinary advice, diagnosis or treatment. When in doubt, call your veterinarian. Sources: Cornell University Feline Health Center; Merck Veterinary Manual; VCA Animal Hospitals; American Association of Feline Practitioners (AAFP)