Guinea pig bladder stones (uroliths) are a common and painful condition causing straining to urinate, blood in the urine, and hunched posture. Calcium oxalate and calcium carbonate stones are most prevalent in guinea pigs, and surgical removal is often required. Dietary calcium restriction is the cornerstone of prevention and recurrence management.
Last reviewed: June 2026
Why Guinea Pigs Get Bladder Stones
Guinea pigs are prone to urolithiasis (bladder and kidney stones) because they naturally excrete large amounts of calcium in their urine — a normal species-specific characteristic. When urine calcium concentration is chronically elevated by a high-calcium diet, crystallization occurs, and stones (uroliths) form in the bladder or, less commonly, the kidneys and ureters.
Calcium oxalate and calcium carbonate are the most common stone types. Bladder sludge (a thick paste of calcium crystals that is not yet consolidated into stones) often precedes stone formation and is itself clinically significant. As described in Quesenberry & Carpenter's Ferrets, Rabbits & Rodents, female guinea pigs are overrepresented in clinical presentations possibly due to anatomical differences, though males develop stones too, with urethral obstruction (a medical emergency) occurring almost exclusively in males due to a narrower urethra.
High-calcium foods are the main dietary risk factor: kale, spinach, broccoli, and alfalfa hay are high-calcium and should be minimized or eliminated in stone-prone guinea pigs. Timothy hay should replace alfalfa hay as the primary roughage. Per the AEMV Pet Care Guides, 2024, adequate water intake (from fresh water and water-rich vegetables) helps dilute urine and reduce crystallization risk.
Signs of Bladder Stones in Guinea Pigs
- Straining to urinate — prolonged squatting, small or no urine output, crying during urination
- Hematuria — blood-tinged urine; visible red or pink discoloration or blood on the cage floor
- Hunched posture — guarding the abdomen; reluctance to move
- Reduced activity and appetite
- Grinding teeth — a sign of pain in guinea pigs
- Weight loss in chronic cases
- Partial or complete urinary obstruction (emergency, more common in males) — inability to urinate at all; rapidly life-threatening
Bladder sludge may produce similar signs without a discrete stone: prolonged straining with small amounts of chalky, thick white urine.
Diagnosis and Treatment
Radiographs are the primary diagnostic tool — calcium-containing stones are radiopaque (visible on plain X-ray). Ultrasound complements radiographs for sludge and small stones. Urinalysis with culture checks for concurrent UTI.
Treatment depends on severity:
- Dietary modification and hydration — for sludge without obstruction; increased water intake, elimination of high-calcium foods, syringe-feeding water if intake is low
- Surgical cystotomy (opening the bladder to remove stones) — the definitive treatment for bladder stones. As described in Quesenberry & Carpenter, guinea pigs tolerate this surgery reasonably well with experienced exotic surgeons; recovery is typically 5–7 days
- Urinary obstruction — an emergency requiring urgent catheterization or cystotomy; guinea pigs with complete urinary blockage can deteriorate within hours
There is no effective medical dissolution protocol for calcium-containing stones in guinea pigs; surgery or patience (for very small stones/sludge) are the realistic options.
When to See a Vet
Call your vet today if:
- Your guinea pig is straining to urinate or producing very little urine
- You see blood in the urine
- Your guinea pig is hunched, grinding teeth, or reluctant to move
Go to the ER immediately if:
- Your guinea pig (especially male) has not urinated for several hours and is straining repeatedly with no output
- Your guinea pig is collapsed, limp, or unresponsive
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Frequently Asked Questions
What diet prevents bladder stones in guinea pigs? Unlimited timothy hay (not alfalfa) as the diet foundation, fresh water always available, and limiting high-calcium vegetables: avoid or minimize kale, spinach, chard, beet greens, and broccoli. Fresh red and green peppers, cucumber, romaine lettuce, and zucchini are lower-calcium options. Avoid mineral supplements or fortified feeds with additional calcium.
Can guinea pig bladder stones dissolve on their own? Calcium oxalate and carbonate stones cannot be dissolved medically in guinea pigs — this is a key difference from cats, where some stone types can be managed with dietary protocols. Small bladder sludge deposits may be manageable with aggressive hydration and dietary change, but established discrete stones require surgical removal.
How much does guinea pig bladder stone surgery cost? Exotic vet exam and radiographs run $150–350. Surgical cystotomy at an exotic specialist costs $600–1,500 depending on facility and geographic region. Post-operative monitoring and hospitalization add $200–400. Emergency surgery for obstruction can run $1,000–2,500 or more given the urgency and intensive support required.
Do bladder stones come back after surgery? Yes — recurrence rates are significant without dietary correction. Guinea pigs that return to a high-calcium diet will redevelop sludge and stones within months to years. Dietary modification and monitoring (periodic X-rays every 6–12 months) are essential to long-term management.
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