Bladder stones (uroliths) in cats cause pain, bloody urine, and — in male cats — the potentially fatal condition of urinary obstruction. Struvite and calcium oxalate are the most common types, each requiring a different treatment approach.
Last reviewed: June 2026
What Are Bladder Stones in Cats?
Feline urolithiasis refers to mineral crystals that aggregate into stones within the urinary tract — most commonly in the bladder (cystic calculi) but occasionally in the kidneys or urethra. As described in Nelson & Couto's Small Animal Internal Medicine, the two predominant types in cats are struvite (magnesium ammonium phosphate — historically the most common, often associated with urinary tract infections in females) and calcium oxalate (now the most prevalent in many studies, especially in older male cats and certain breeds). These two types form under opposite urine pH conditions, require different dietary management, and have different treatment implications. Feline urolithiasis is closely associated with feline lower urinary tract disease (FLUTD), which affects 1–3% of cats presenting to veterinary practices annually. IRIS CKD Staging Guidelines, 2023 recommend urinalysis as a component of regular kidney health monitoring in cats over 7 years, as stones can coexist with and accelerate kidney disease.
Signs of Bladder Stones in Cats
- Hematuria (blood in urine — urine appears pink, red, or rust-colored)
- Straining to urinate (dysuria) — squatting repeatedly without producing much urine
- Frequent, small urinations (pollakiuria)
- Crying or vocalizing during urination
- Licking at the urinary opening
- Urinating outside the litter box — often on cool surfaces
- In male cats: complete inability to urinate (obstruction) — a LIFE-THREATENING EMERGENCY
- Lethargy and loss of appetite if obstruction has caused uremia
Diagnosis
X-rays (most struvite and some calcium oxalate stones are visible) and ultrasound are standard first steps. Double-contrast cystography reveals stones not visible on plain X-ray. Urinalysis with sediment examination identifies crystals, infection, and blood. Urolith type is definitively determined by stone analysis from a laboratory (after removal or passage).
Treatment
Struvite stones associated with UTI can often be dissolved using prescription dissolution diets (acidifying, low magnesium) over 4–12 weeks combined with antibiotic treatment of any infection. Sterile struvite stones dissolve on prescription diet alone.
Calcium oxalate stones do NOT dissolve with diet — surgical removal (cystotomy) or non-surgical hydropulsion is required. Prevention focuses on increasing water intake (wet food, water fountains), urine dilution, and dietary adjustments to reduce oxalate and calcium load.
Urethral obstruction (male cats): emergency unblocking under sedation, urinary catheterization, IV fluids, correction of hyperkalemia (which can cause fatal cardiac arrhythmia), and hospitalization. This is a medical emergency with a mortality rate of approximately 20–30% if treatment is delayed more than 24 hours.
Costs
Urinalysis and imaging: $200–450. Prescription dissolution diet trial (3 months): $100–300. Surgical cystotomy: $1,200–2,800. Emergency treatment of urethral obstruction: $1,500–4,000 for hospitalization plus catheterization and supportive care. Perineal urethrostomy (surgical widening of the urethral opening for cats with repeated obstructions): $2,500–4,500.
When to See a Vet
Call your vet today if:
- Your cat is straining to urinate and producing small amounts of bloody urine
- Urination outside the litter box began suddenly without a behavioral explanation
- You see blood in the urine more than once
Go to the ER immediately if:
- Your male cat has been straining to urinate for more than 2–4 hours without producing urine
- Cat is crying, lethargic, or vomiting alongside urinary straining
- Cat's abdomen feels hard or he's hiding and not moving
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Frequently Asked Questions
Can bladder stones in cats go away on their own? Struvite stones associated with UTI can occasionally dissolve once the infection is treated, but most stones require active management. Calcium oxalate stones never dissolve on their own and require removal. Unmanaged stones cause ongoing pain, infection, and can lead to life-threatening urethral obstruction in male cats.
How do I know if my cat is blocked vs. just straining? A blocked male cat that cannot urinate at all typically shows progressive distress over hours — straining repeatedly with no urine output, crying, retching, or becoming completely lethargic. This is an emergency that can be fatal within 24–48 hours without treatment. If there is any doubt, go to an ER immediately.
What does treating cat bladder stones cost? Diagnosis and medical management of struvite stones runs $400–800 total. Surgical removal (cystotomy) for calcium oxalate stones costs $1,200–2,800. Emergency unblocking of a male cat costs $1,500–4,000. Preventive prescription diet ongoing: $50–100/month.
What diet helps prevent cat bladder stones? Increasing water intake is the single most important preventive measure — wet food, water fountains, and multiple water bowls dramatically dilute urine. For struvite prevention: urinary acidifying diets (pH 6.0–6.5). For calcium oxalate: urine dilution is primary; some prescription diets reduce oxalate and calcium absorption. WSAVA Global Nutrition Guidelines, 2011 endorse body condition monitoring and appropriate diet selection as key components of preventing urinary tract disease.
Are certain cat breeds more prone to bladder stones? Yes — Burmese, Himalayan, and Persian cats are over-represented for calcium oxalate stones. Siamese cats have higher rates of some crystal types as well. Neutered male cats of any breed are at higher risk for urethral obstruction due to the narrower urethra.
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