Guinea Pig Bladder Stones & UTIs: Signs, Causes & Care

Few things rattle a guinea pig owner like a pink smear on the bedding or a tiny squeak of pain when your piggy pees. Urinary problems — bladder stones, gritty bladder “sludge,” and urinary tract infections (UTIs) — are some of the most common health issues we see in pet guinea pigs, and they often look frightening before they look serious. The reassuring part: these are well understood by exotic vets, and a lot of what causes them sits in your hands at feeding time.

This guide covers what bladder stones, sludge, and UTIs actually are, the warning signs to watch for, which ones mean “phone the vet now,” and how vets diagnose and treat each. Then we’ll cover the prevention you genuinely control — hay, water, vitamin C, and a sensible eye on calcium. After years of weekly weigh-ins with my own herd, one lesson keeps proving itself: catching a urinary problem early, and getting a vet involved fast, makes all the difference.

Quick answer: Bladder stones, sludge, and UTIs all irritate a guinea pig’s urinary tract and share the same red flags — blood in the urine, straining, or squeaking when peeing. Any of these means see an exotic vet promptly. A guinea pig that is straining but cannot pass any urine is a life-threatening emergency — go to a vet immediately. Stones almost always need surgical removal; there is no safe way to dissolve them at home.

Last reviewed and updated for 2026 — current vet guidance on bladder stones, sludge, and UTIs, a symptom table, the emergency signs, and a balanced, vet-approved prevention plan.

This guide is for information only and isn’t a substitute for veterinary advice — always consult an exotic or small-animal vet about your guinea pig.

Table of Content

What are bladder stones, sludge, and UTIs?

These three problems sit on the same spectrum of urinary trouble, which is why they’re so easy to confuse — and why a vet groups them together. Bladder stones (uroliths) are hard, solid mineral deposits that form in the bladder, usually made of calcium carbonate or calcium phosphate. Bladder sludge is thick, gritty, calcium-rich sediment in the urine — essentially the crystal “sand” that can settle out before it ever becomes a solid stone. A urinary tract infection (UTI) is a bacterial infection of the bladder or urethra that inflames the lining and often causes bleeding.

These three frequently overlap and feed into one another, and they produce nearly identical symptoms — blood, straining, and pain. That’s exactly why you can’t safely diagnose the difference at home: it takes a vet’s imaging and a urine test to tell them apart. Stones can form anywhere along the tract (kidneys, ureters, bladder, or urethra), but the bladder is by far the most common spot.

One important reassurance first: guinea pig urine is naturally cloudy, chalky, and often creamy-white because they pass excess calcium in their pee. That milky look on its own is normal and not a sign of disease. What you’re watching for is red, pink, orange, or brown urine, or genuine pain — not ordinary cloudiness.

Why are guinea pigs so prone to urinary stones?

Guinea pigs have an unusual quirk of biology: unlike most mammals, they absorb dietary calcium very efficiently and then dump the excess straight into their urine. That makes their pee naturally rich in calcium — and when conditions are wrong, that calcium can crystallise into sludge and stones. Several risk factors stack on top of that baseline:

Too much dietary calcium — the biggest lever. Feeding adult guinea pigs alfalfa hay or alfalfa-based pellets (both very high in calcium), or giving high-calcium vegetables every day, raises the calcium load their bladder has to handle.
Not drinking enough water — low water intake and chronic dehydration concentrate the urine, so crystals settle out and clump together instead of being flushed away.
Too little exercise and excess weight — an inactive, overweight piggy moves urine through the bladder more sluggishly, giving sediment time to build up.

Individual and genetic factors — some guinea pigs simply form stones more readily than others, even on a good diet, and may form them again after treatment.
Existing infection or inflammation — a UTI can change the bladder environment in ways that encourage crystals, and stones in turn irritate the bladder and invite infection. The problems reinforce each other.

The encouraging takeaway is that the two biggest risk factors — calcium and hydration — are things you manage directly through diet and fresh water. We’ll come back to a balanced, vet-approved prevention plan below. (And to be clear: the goal is balance, not starving your pig of calcium, which they still need.)

Symptoms and warning signs

Because guinea pigs are prey animals, they instinctively hide illness, so any obvious urinary sign usually means they’ve been uncomfortable for a while. Watch closely if you spot any of the following, and use the table to gauge how worried to be.

Sign you may notice	What it can mean	How urgent
Blood in the urine (red, pink, orange or brown pee; red spots on bedding)	Stones, sludge, or a UTI irritating the bladder lining	See a vet promptly (within a day)
Straining, crying or squeaking when peeing	Painful urination from stones, gritty sludge, or infection	See a vet promptly
Frequent small dribbles of urine	Bladder irritation or partial obstruction	See a vet promptly
Hunched posture, sitting in a tense ball	Abdominal or urinary pain	See a vet promptly
Wet, stained or scalded bottom and inner legs	Dribbling urine; urine scald irritating the skin	See a vet soon
Loss of appetite, lethargy, hiding more than usual	Pain or systemic illness; risk of gut slowdown	Urgent — not eating is an emergency
Straining but producing little or NO urine	Possible blocked urethra (more common in males)	EMERGENCY — vet now

Keep in mind that some stones cause no symptoms at all and are only found by chance during a check-up or an X-ray for something else — another reason regular vet visits and home weigh-ins matter. If you’re unsure whether a symptom is urinary or something else entirely, our guinea pig health symptom checker can help you narrow it down before you call.

Is it an emergency?

Most urinary problems need a prompt (next-day) vet visit rather than a midnight dash — but a few situations are true emergencies where minutes matter. Go to a vet immediately if your guinea pig is straining to urinate but cannot pass anything. A stone can lodge in the narrow urethra and block the flow entirely (males are especially at risk). A complete blockage causes urine to back up, which is intensely painful and can damage the kidneys or rupture the bladder within hours. It is genuinely life-threatening.

Treat it as an emergency — call an exotic vet or emergency clinic right away — if you see any of these:

No urine being passed despite obvious, repeated straining.
Your guinea pig has stopped eating — a piggy that won’t eat for 12–24 hours can develop dangerous gut stasis and needs same-day care.
Collapse, extreme lethargy, cold to the touch, or crying out in pain.

A hard, distended, painful belly.

If it’s “just” blood in the urine, mild straining, or a stained bottom with your pig still eating and acting normally, that still warrants a prompt appointment — book it the same or next day rather than waiting to “see if it clears up.” It rarely does on its own.

How vets diagnose and treat urinary problems

Because stones, sludge, and UTIs look so alike from the outside, your vet’s first job is to work out which one (or which combination) you’re dealing with. Diagnosis is firmly vet-led and usually involves:

A hands-on exam — gently feeling the abdomen and bladder, and checking weight and overall condition.

X-rays (radiographs) — calcium-based stones show up clearly on imaging, so an X-ray (often two views) is the key test for confirming and locating stones. Ultrasound may be added for sludge.
Urinalysis, and sometimes a urine culture — checking the urine for blood, crystals, bacteria, and white blood cells to identify infection and crystal type.
Blood tests — in some cases, to assess kidney function and the pig’s fitness for anaesthesia.

Treatment depends on the diagnosis, and your vet will tailor it to your individual pig. Here’s what the options generally look like:

Bladder stones — usually surgery. In most cases stones must be removed surgically, in an operation called a cystotomy (the vet opens the bladder and lifts the stones out). Crucially, there is no reliable way to dissolve guinea pig bladder stones with diet or medication the way some dog and cat stones can be — so home “dissolving” remedies don’t work and delay proper care.
Sludge — flushing and supportive care. Thick sludge may be flushed from the bladder by the vet (often under sedation or anaesthetic), alongside fluids and a plan to dilute the urine and reduce calcium going forward.

UTIs — a course of antibiotics. Bacterial infections are treated with vet-prescribed antibiotics, frequently for two weeks or longer to let the bladder lining heal, plus pain relief. Your vet chooses the right medicine and dose for your pig — never give human painkillers or leftover antibiotics.
Pain relief and fluids are common across all three, because these conditions hurt and hydration helps the urinary tract recover.

Your vet may also send a removed stone for analysis to learn what it’s made of, which helps shape a prevention plan and gauge the risk of new stones forming. Recurrence is common, so follow-up checks are part of the deal.

Prevention and home care

You can’t change your guinea pig’s calcium-shedding biology or its genes, but you can tilt the odds heavily in their favour. Prevention is where owners have the most power, and it comes down to a balanced diet and plenty of water. Aim for sensible moderation, not a calcium crackdown.

Feed grass hay, not alfalfa, to adults. Unlimited timothy or other grass hay should make up about 80% of the diet — it’s low in calcium and great for teeth and gut. Save alfalfa for babies, pregnant, or nursing pigs. See our guide to the best hay for guinea pigs.
Choose timothy-based pellets and feed them in moderation. Skip alfalfa-based pellets for adults — they’re calorie- and mineral-dense.

Go easy on high-calcium vegetables. Spinach, kale, parsley, and other dark greens are healthy in rotation but shouldn’t be daily staples — offer them a few times a week rather than free-choice. Don’t cut them out entirely, though; variety matters.
Keep water fresh and plentiful. Clean, full water sources encourage drinking, which dilutes the urine and flushes crystals out. Water-rich veg like cucumber helps too. If you have very hard tap water, ask your vet about offering filtered or low-mineral water.
Don’t skimp on vitamin C — but don’t put it in the water bottle. Guinea pigs can’t make their own vitamin C and need a daily supply through fresh food or a proper supplement. Avoid dumping vitamin C drops in the water (it degrades fast and can put pigs off drinking). If your pig is missing out, read up on guinea pig scurvy and our vitamin C food list.

Encourage exercise and a healthy weight. Daily floor time keeps urine moving and weight in check. A simple kitchen-scale weigh-in once a week is one of the best early-warning tools you have — steady weight loss often signals trouble before anything else shows.
Keep bedding clean and dry. A clean, absorbent floor helps prevent urine scald on a pig that’s dribbling, and lets you spot blood spots early. See our pick of the best bedding for guinea pigs.

If your pig is recovering from treatment, keep them warm, quiet, eating, and hydrated, and follow your vet’s instructions to the letter — especially finishing the full course of any antibiotic. Our beginner’s guide to guinea pig care ties the whole daily routine together.

When to see a vet

Here’s the simple rule to hold onto: blood in the urine or straining to pee always deserves a prompt visit to an exotic or small-animal vet, and a pig that can’t urinate at all is an emergency — go straight away. These conditions don’t resolve on their own, and the longer a stone or infection goes untreated, the more your guinea pig suffers and the more complicated treatment becomes.

You know your piggy best. If something about their peeing, posture, appetite, or energy feels off, trust that instinct and pick up the phone — a quick call to a vet who knows guinea pigs is never an overreaction. For the bigger picture of guinea pig health, browse our full list of guinea pig illnesses.

Frequently asked questions

Is blood in my guinea pig’s urine always serious?

Blood in the urine (red, pink, or brown pee) always warrants a prompt vet visit. It usually points to a bladder stone, sludge, or a UTI, none of which clear up on their own. Don’t confuse it with normal cloudy, creamy-white guinea pig urine, which is just excess calcium and is harmless.

Can guinea pig bladder stones be dissolved without surgery?

No. Unlike some dog and cat stones, there is no reliable diet or medication that dissolves guinea pig bladder stones, so surgical removal (a cystotomy) is usually needed. Home “dissolving” remedies don’t work and only delay the care your pig needs. Very small stones occasionally pass on their own under vet supervision.

What does a urinary blockage look like, and what should I do?

A blocked guinea pig strains repeatedly but passes little or no urine, often crying out, hunched, and refusing food. This is a life-threatening emergency, especially in males. Go to an exotic or emergency vet immediately — a complete blockage can damage the kidneys or rupture the bladder within hours.

Should I stop feeding my guinea pig calcium to prevent stones?

No — guinea pigs still need some calcium, so the goal is balance, not elimination. Feed grass hay instead of alfalfa to adults, offer high-calcium vegetables like kale and spinach only a few times a week rather than daily, and make sure your pig always has fresh water to keep the urine dilute.

Are male or female guinea pigs more at risk?

Both sexes form stones and sludge, but males are more prone to a dangerous urethral blockage because their urethra is longer and narrower, so a stone can lodge and stop urine flow entirely. Any straining male that can’t pass urine needs emergency care without delay.

Will my guinea pig get bladder stones again after surgery?

Recurrence is unfortunately common, because the same calcium-rich biology remains. Sticking closely to a vet-guided prevention plan — grass hay, moderate calcium, plenty of water, exercise, and weekly weigh-ins — lowers the risk, and regular check-ups help catch any new stones early.

Related Guinea Pig Guides

List of Sources

VCA Animal Hospitals — Bladder Sludge and Bladder Stones in Rabbits and Guinea Pigs

Merck Veterinary Manual — Guinea Pigs (Disorders and Diseases)

Veterinary Partner (VIN) — Urinary Stones in Guinea Pigs

Royal Veterinary College — Guinea Pig Urolithiasis: Diet Advice