Rabbit cystitis — bladder inflammation usually from infection, sludge, or bladder stones — shows up as urine staining around the perineum, straining, blood-tinged urine, and a hunched posture. Sediment-heavy "sludge" urine is the classic rabbit presentation and is uniquely tied to dietary calcium handling (Oglesbee & Lord, 2010, JEPM). Most cases respond to fluid therapy, pain control, and a lower-calcium diet, but recurrent or stone-positive cases need imaging and sometimes surgery.
Last reviewed: June 2026
What Rabbit Cystitis Is
Cystitis in rabbits is inflammation of the urinary bladder wall, usually from one of three causes: bacterial urinary tract infection (often Pasteurella or E. coli), bladder sludge (thick paste of calcium carbonate crystals), or true bladder stones (uroliths). Rabbits absorb dietary calcium passively rather than under tight hormonal control, so excess dietary calcium is excreted in the urine, predisposing to crystal and stone formation. Adult overweight rabbits on alfalfa-based diets are over-represented.
Signs Owners First Notice
Wet, urine-stained fur around the perineum and inner hind legs (urine scald) is often the first sign. Owners also see straining in the litter box for prolonged periods, frequent small-volume urinations, blood-tinged urine (true hematuria), hunched posture, teeth-grinding from discomfort, and reduced appetite. Litter that is unusually heavy or has thick paste-like residue on the bottom suggests bladder sludge. Recurrent urine accidents outside the box in a normally clean rabbit is a red flag.
Why "Red Urine" Doesn't Always Mean Cystitis
Healthy rabbits sometimes produce dark red or orange urine from plant pigments (particularly after carrots, dandelions, or spinach) — this is porphyrin pigmentation, not blood. True hematuria is usually accompanied by other signs (straining, posture changes, weight loss). A urine dipstick blood test or microscopic exam differentiates the two. As reviewed in Quesenberry and Carpenter's Ferrets, Rabbits, and Rodents, owners commonly mistake pigment for blood and vice versa.
How It's Diagnosed
Urinalysis with sediment exam, urine culture, and abdominal radiographs are the foundation, as detailed in the AEMV pet care resources for urinary disease in rabbits (AEMV Pet Care Guides, 2024). Radiographs reliably show calcium-based stones because rabbit urine is highly mineralized. Ultrasound visualizes sludge thickness and bladder wall changes. A complete blood count and chemistry assesses kidney function. The Carpenter Exotic Animal Formulary documents appropriate antibiotic selection — trimethoprim-sulfamethoxazole or enrofloxacin are common rabbit-safe choices.
Treatment
Acute cases need IV or subcutaneous fluid therapy to flush sediment, analgesia with meloxicam (0.6 to 1.0 mg/kg once to twice daily) and sometimes opioids, and culture-directed antibiotics when bacterial infection is confirmed. Bladder expression under sedation removes thick sludge in many cases. Dietary modification is essential long-term: unlimited grass hay (timothy, orchard), elimination of alfalfa pellets in adult rabbits, controlled greens, and unlimited water access through a heavy bowl. Bladder stones require surgical cystotomy.
When to See a Vet
Call your vet today if:
- Urine-stained fur around the perineum or inner thighs
- Straining in the litter box for more than 1 to 2 minutes
- Blood-tinged urine that is not the usual orange pigment color
- A previously litter-trained rabbit having frequent accidents
- Reduced appetite combined with hunched posture
Go to the ER immediately if:
- A rabbit who hasn't urinated in 12 hours despite straining
- Severe lethargy with cold ears and rapid breathing
- A rabbit who stops eating completely for more than 12 hours (GI stasis)
- Sudden inability to use the back legs
- A rigid, painful abdomen
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Frequently Asked Questions
How can I tell sludge from blood in the urine?
Sludge appears as a thick, opaque paste — often beige, white, or yellowish — at the bottom of the litter box. Blood-tinged urine looks watery red or pink in the urine itself and stains absorbent surfaces uniformly. Pigment urine is reddish-orange but normal in volume and consistency. When in doubt, photograph the urine and bring a sample to the vet.
How much does diagnosis and treatment cost?
Initial exotic vet exam typically runs $75 to $200 in the US. Urinalysis with culture and sensitivity costs $80 to $200. Radiographs add $150 to $400. Ultrasound is $200 to $500. A 2 to 3 week antibiotic course runs $40 to $120 depending on agent. Bladder expression under sedation is $200 to $500. Cystotomy for stone removal at an exotic surgery referral is $1,500 to $4,000. Catching sludge early with dietary change is dramatically cheaper than surgical stone removal.
What is the right rabbit diet to prevent cystitis?
Unlimited grass hay (timothy, orchard, meadow) should make up roughly 80 percent of intake. Adult rabbits should not eat alfalfa hay or alfalfa pellets, which are very high in calcium. Grass-based pellets are limited to about 1/8 to 1/4 cup per 2 kg body weight per day. Fresh greens are offered daily but in measured amounts, with high-calcium greens (kale, parsley, dandelion in excess) limited.
Can rabbits get UTIs without sludge or stones?
Yes — bacterial UTIs occur independently of urolithiasis, especially in older rabbits or rabbits with arthritis who cannot fully empty the bladder. Culture-directed antibiotics and addressing any underlying mobility issue are essential.
Still Not Sure if Your Rabbit Needs a Vet?
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