Guinea pig bladder stones (uroliths) are among the most common urinary problems in this species — calcium carbonate stones form in the bladder and cause pain, blood in the urine, and straining. Surgery is often required, and the sooner you act, the better the outcome.
Last reviewed: June 2026
What Are Bladder Stones in Guinea Pigs?
Bladder stones (urolithiasis) occur when minerals precipitate out of urine and form solid deposits in the bladder, urethra, or — less commonly — the ureters. Guinea pigs are highly predisposed to this condition, and their uroliths are almost exclusively composed of calcium carbonate, which is rarely seen as the primary stone type in other companion animals.
Research confirms that uroliths in guinea pigs are most commonly located in the bladder, followed by the urethra (Kamphues, 1991, JEPM — composition study, PubMed PMID 19210239). Female guinea pigs may be more commonly affected clinically, though both sexes develop stones. Diet — particularly high-calcium greens, low moisture intake, and concentrated urine — is the primary risk factor, as described in Quesenberry & Carpenter's Ferrets, Rabbits & Rodents: Clinical Medicine and Surgery.
Signs of Bladder Stones in Guinea Pigs
Guinea pigs are stoic animals that mask pain well, making early detection difficult. Watch for:
- Straining to urinate (stranguria) — posturing repeatedly in the litter area with little or no urine output
- Blood in urine (haematuria) — pink, red, or rust-coloured urine; may be intermittent
- Vocalising while urinating — squeaking or crying during urination indicates significant pain
- Reduced or absent urine output — a urethral stone causing obstruction is a medical emergency
- Hunched posture — guinea pigs with abdominal pain hunch and move less
- Weight loss and reduced appetite — secondary to chronic pain and discomfort
- Wet perineum — urine dribbling or leaking, often with skin irritation or scalding around the genitals
A retrospective study of 158 guinea pigs with urolithiasis found age, body weight, and dietary factors to be significant risk factors, with high-moisture foods (moisture content >50%) such as bell peppers, tomatoes, and romaine lettuce being strongly protective (JAVMA Retrospective, 2022).
Diagnosis
Your vet will use several tools:
- Physical examination — palpation of the abdomen; bladder stones in guinea pigs are often large enough to be felt
- Radiographs (X-rays) — calcium carbonate stones are dense and highly visible; a quick, low-cost first step; exotic vet X-rays typically cost $150–300
- Urinalysis — reveals haematuria, crystalluria, elevated pH; also screens for concurrent infection
- Ultrasound — useful for assessing bladder wall, stone number, and urethral involvement; $300–600
Treatment
Surgical removal (cystotomy) is the most definitive treatment for bladder stones in guinea pigs. There is no reliable medical dissolution protocol for calcium carbonate uroliths in this species. The procedure involves opening the bladder under general anesthesia and removing the stone(s). Exotic vet surgery typically costs $800–2,000 depending on stone size and complexity.
Urethral obstruction — if a stone blocks the urethra, the guinea pig cannot urinate and requires emergency intervention. An obstructed guinea pig is in a life-threatening situation; without intervention, uremia develops within hours.
Post-operative care includes pain management, antibiotics if infection is present, and dietary changes to reduce recurrence risk. The AEMV Pet Care Guides, 2024 recommend increasing dietary moisture through fresh vegetables and water sources as the primary long-term prevention strategy.
When to See a Vet
Call your vet today if:
- You notice blood in your guinea pig's urine
- Your guinea pig is straining or crying while urinating
- Your guinea pig has a wet, irritated bottom or is producing less urine than normal
- Your guinea pig is hunched, less active, or eating less
Go to the ER immediately if:
- Your guinea pig has not produced any urine and is straining repeatedly — this is a urethral obstruction emergency
- Your guinea pig is collapsed, unresponsive, or grinding teeth in distress
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Frequently Asked Questions
How much does bladder stone surgery cost for a guinea pig? Exotic vet exam and radiographs typically run $200–400. Cystotomy (bladder stone removal) surgery under anesthesia costs $800–2,000 at most exotic vet practices, reflecting the 1.5–2× exotic vet premium over standard rates. Post-operative pain medication and antibiotics add $50–100. Emergency care for obstruction can cost $1,000–2,500 or more. Catching stones before obstruction occurs reduces costs significantly.
Can bladder stones in guinea pigs dissolve on their own? No. Calcium carbonate uroliths do not dissolve with diet change alone. Surgery is the only reliable way to remove established stones. Diet modification after surgery helps prevent recurrence but will not eliminate stones already present.
What foods should I avoid to prevent bladder stones in guinea pigs? Reduce high-calcium greens such as kale, spinach, and collard greens. Favour lower-calcium alternatives like romaine lettuce, bell pepper, and cucumber. Ensure constant access to fresh water. High-moisture fresh vegetables reduce urinary concentration and lower stone risk.
Can bladder stones recur after surgery? Yes, recurrence is common, particularly if diet and hydration are not changed. Some guinea pigs develop new stones within months. Long-term dietary management and regular vet check-ups (including periodic X-rays) are the best way to detect recurrence early.
Is a guinea pig with a bladder stone in pain? Yes. Even without a complete obstruction, stones irritate the bladder wall and cause ongoing pain. A guinea pig with urolithiasis is uncomfortable and needs veterinary care promptly.
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