Blood in a Dog or Cat's Urine: Causes and What to Do

Seeing pink, red or brown urine — or spots of blood where your pet has urinated — is understandably alarming. Blood in the urine, known medically as hematuria, is a sign rather than a diagnosis. It tells you something in the urinary system needs attention, but not by itself what that something is.

Hematuria ranges from a minor, easily treated issue to a genuine emergency, and the difference is not always obvious from the color alone. This guide explains where urinary blood comes from, the common causes in dogs and cats, one situation that is a true emergency, what your veterinarian will check, and the daily habits that support a healthy urinary tract.

Important: This article shares general educational information for pet owners and is not a substitute for an in-person veterinary examination, diagnosis, or treatment. For any medical concern or emergency, contact your veterinarian promptly.

What Hematuria Looks Like

Blood can tint urine anywhere from faintly pink to deep red or a rusty brown. Sometimes it is obvious in a puddle or on a pee pad; other times it is only detectable under a microscope during a routine urine test. On light-colored litter, cat urine spots may look reddish or leave pink-tinged clumps.

Not every red or dark urine is blood — some pigments from food, medications or muscle breakdown can discolor urine too. That is exactly why laboratory testing matters: your veterinarian can confirm whether true blood cells are present and begin to work out where they are coming from.

Where Urinary Blood Comes From

The urinary system runs from the kidneys, down the ureters, into the bladder, and out through the urethra. Blood can enter at any point along that path, and the accompanying signs give clues:

• Kidneys: bleeding here is often painless and may come with increased thirst or other whole-body signs.
• Bladder: by far the most common source; usually paired with straining, frequent small urinations and discomfort.
• Urethra: especially in male animals, where stones or plugs can lodge and cause visible blood and straining.
• Reproductive tract: in unspayed females, the source can be the uterus or vagina rather than the urinary tract itself.

Common Causes in Dogs

• Urinary tract infections: bacterial infection of the bladder is a frequent cause, more common in female dogs.
• Bladder stones: mineral stones irritate the bladder lining and can cause both blood and straining.
• Injury or trauma: a fall or being hit can bruise or tear urinary structures.
• Prostate problems: in intact male dogs, prostate enlargement or infection can cause bloody urine.
• Pyometra: in unspayed females, a serious uterine infection can look like urinary blood and is an emergency.
• Clotting disorders and toxins: certain rat poisons and clotting problems cause bleeding, including into the urine.
• Bladder growths: less common, and more likely in older dogs; another reason persistent hematuria needs investigation.

Common Causes in Cats

In cats, one umbrella condition dominates the conversation: feline lower urinary tract disease (FLUTD). This is a group of problems affecting the bladder and urethra, and blood in the urine is one of its hallmark signs.

• Feline idiopathic cystitis: stress-associated bladder inflammation is the single most common cause of bloody, painful urination in cats, often with no infection found.
• Bladder stones and crystals: mineral deposits irritate the bladder and can contribute to blockages.
• Urethral plugs: gritty material can block the urethra, especially in male cats — a medical emergency.
• Infections: less common in young cats than in dogs, but more likely in older cats or those with other diseases.
• Other conditions: diabetes, kidney disease and, rarely, tumors can play a role, particularly in senior cats.

A True Emergency: The Cat Who Cannot Urinate

This point deserves its own section because it saves lives. A cat — most often a male cat — who is straining in the litter box, producing little or no urine, crying, pacing, vomiting or hiding may have a urethral blockage. This is one of the most time-critical emergencies in feline medicine. A complete blockage can become life-threatening within a day or two as toxins and potassium build up.

If you suspect your cat cannot pass urine, do not wait to see if it improves — contact your veterinarian or an emergency clinic immediately. Straining in a litter box is easy to mistake for constipation, so when in doubt, have it checked right away.

Signs to Watch Alongside the Blood

The company hematuria keeps helps your veterinarian narrow the cause. Note whether you see:

• Straining or frequent trips with only small amounts produced.
• Accidents in a previously house-trained pet, or a cat urinating outside the box.
• Excessive licking of the genital area.
• Signs of pain: vocalizing while urinating, a hunched posture, restlessness.
• Increased thirst or larger urine volumes, which point more toward the kidneys or whole-body disease.
• Lethargy, vomiting or appetite loss, which raise the urgency considerably.

Jot down when the blood started, how often your pet urinates, and any change in behavior. These details are genuinely useful at the clinic.

How Veterinarians Investigate

Because hematuria has so many possible causes, your veterinarian works methodically:

• Urinalysis: the first and most informative test — confirms blood, checks for infection, crystals, and how concentrated the urine is.
• Urine culture: identifies bacteria and guides antibiotic choice when infection is present.
• Blood work: assesses kidney function, blood cell counts and clues to whole-body disease.
• Imaging: X-rays and ultrasound reveal stones, bladder wall changes, prostate or uterine problems and masses.
• Blood pressure and clotting tests: used when the pattern suggests bleeding disorders or hypertension.

Try to bring a fresh urine sample if you can collect one cleanly, but never delay an urgent visit to obtain one — the clinic can collect a sample safely.

How Causes Are Managed

Treatment follows the diagnosis, and your veterinarian will tailor it to your pet. In broad terms, infections are treated with appropriate antibiotics guided by culture; some stones are dissolved with special diets while others require removal; urethral blockages are relieved urgently and then managed to prevent recurrence; and stress-related feline cystitis is managed with environmental changes, increased water intake and stress reduction rather than antibiotics.

Because the right treatment depends entirely on the cause, home remedies are not a substitute for diagnosis. Do not give leftover antibiotics or human urinary products; some are ineffective or unsafe, and masking signs can delay important care.

Supporting Urinary Health Day to Day

Once a cause is addressed, several everyday habits support the urinary tract and can reduce the odds of recurrence, especially in cats prone to cystitis:

• Encourage water intake: fountains, wide bowls, multiple stations and wet food all raise fluid intake and dilute the urine.
• Keep litter boxes pristine: cats avoid dirty boxes; the rule of thumb is one box per cat plus one, scooped daily.
• Reduce stress: predictable routines, hiding spots, vertical space and calm introductions help stress-sensitive cats.
• Maintain a healthy weight: obesity is a risk factor for urinary problems.
• Feed appropriately: follow veterinary diet advice, especially after stones or crystals.

MetaPet's Easy Check-Up color-changing litter and Smart Easy Check-Up pee pad are designed to help you keep an eye on your pet's urine at home, changing color in the contact area so you can compare against the included chart and notice changes worth raising with your veterinarian. For neutered and sterilized cats, MetaPet also offers cranberry-containing urinary support pastes and drops formulated to support normal urinary tract function as part of a daily routine. These wellness aids support monitoring and everyday care — they do not diagnose, treat or replace veterinary evaluation of blood in the urine, which always warrants a professional exam.

When to Call Your Veterinarian

Blood in the urine always deserves a veterinary conversation, but the timing depends on the whole picture. Seek emergency care immediately if a cat is straining with little or no urine, or if any pet is collapsed, repeatedly vomiting, or has swallowed a possible toxin. Book a prompt (same-day or next-day) appointment for visible blood with straining or discomfort, or for a pet who is otherwise bright but clearly uncomfortable.

Even a single episode of blood-tinged urine in a bright, comfortable pet is worth a call — a quick urine test often catches an easily treated problem before it worsens.

Frequently Asked Questions

My pet seems fine otherwise — can I just watch it?

A pet who is bright and eating is reassuring, but hematuria still warrants a call. Some serious causes cause little discomfort early on, and a simple urine test is quick and informative.

Could it be something my pet ate?

Some pigments can discolor urine, but you cannot reliably tell food coloring from true blood by eye. Let testing make that distinction.

Is blood in the urine painful?

Often, yes — particularly with bladder inflammation, stones or blockages. Straining, frequent trips and vocalizing suggest discomfort and add urgency.

My unspayed dog has bloody discharge — is that hematuria?

Not necessarily. Discharge from the reproductive tract can look identical to urinary blood on the floor. In an unspayed female, a heat cycle is one possibility, but so is pyometra — a serious uterine infection, especially in the weeks after a heat, often with lethargy, increased thirst and appetite loss. Any unspayed female with bloody discharge and a change in how she feels needs prompt veterinary assessment.

How long does it take for hematuria to resolve?

It depends entirely on the cause. A straightforward bladder infection often improves within days of appropriate treatment. Bladder stones may need weeks of dietary dissolution or surgical removal. Stress-related cystitis in cats frequently settles within a week or two but tends to recur if the underlying stress is not addressed. Your veterinarian will advise when to recheck a urine sample to confirm the problem has truly resolved rather than just become invisible.

Collecting a Urine Sample at Home

A clean sample speeds up diagnosis considerably, and many owners can collect one with a little preparation. For dogs, a shallow clean container or a ladle taped to a stick lets you catch mid-stream urine during a normal walk without crowding your pet. Approach quietly from the side once they have started, and do not chase — a missed attempt is fine, there will be another chance.

For cats, ask your clinic for non-absorbent litter substitute, which looks like small plastic beads. Empty a clean box, add a thin layer, and confine your cat with the box for a few hours. The urine pools on the surface and can be poured into a container.

• Use a clean container: rinse and dry thoroughly; residue can affect results.
• Refrigerate promptly: keep the sample cool and get it to the clinic within a few hours if possible.
• Note the time: first-morning urine is the most concentrated and often the most informative.
• Do not delay urgent care: if your pet is unwell or straining, go to the clinic without a sample.

If home collection proves impossible, do not worry. Veterinary teams routinely collect samples safely and quickly, and a sample taken at the clinic is often preferable for culture because it avoids contamination.