Blood in Cat Urine

Katie Grzyb, DVM
By Katie Grzyb, DVM on May 15, 2023

Hematuria, or bloody urination, can be terrifying when you are uncertain what caused it in your cat. Bright red blood can be seen in the urine of cats for multiple reasons, ranging from bacterial infection to general inflammation from stress. Diagnosis of the underlying cause of the hematuria is necessary to start the right treatment for your cat.

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What Does Blood in Cat Urine Look Like?

Cat urine should be a light-yellow color with a slight odor of ammonia. Darker yellow and more potent urine can be noted with dehydration or after a long time of rest (such as after not urinating overnight), and this is usually considered normal.

If bright red blood, pink tinge to the urine, orange discoloration, or brown discoloration is noted or if the urine seems to be foamy or has blood clots in it, then a visit to the veterinarian is needed to further investigate the cause of these changes in color and consistency.

Sometimes no other symptoms are noted with this bloody urination, which is why it is so important to watch the litter box closely for any changes in urination or defecation.

Other common clinical signs that can be found alongside bloody urination include:

  • Straining to urinate

  • Frequent visits to the litter box

  • Vomiting

  • Changes in appetite

  • Drinking more water

  • General lethargy

What To Do if Your Cat Is Peeing Blood

If you notice blood in your cat’s urine or any of the above clinical signs, contact your veterinarian immediately.

If you have a male cat at home that is visiting the litter box frequently, straining to urinate with little to no urine production, or is licking at their penis consistently, bring them to a veterinarian immediately for evaluation of a possible urinary blockage. Blockage of the urethra (the tube that carries urine from the bladder to the outside environment) is considered a medical emergency, and if not diagnosed and treated as soon as possible, it is fatal.

What Causes Blood in Cat Urine?

There are many causes of hematuria in cats, depending on where the underlying medical issue is in the body. These causes include:

Upper urinary tract (including the kidneys and the ureters, the tubes that carry urine from the kidneys to the bladder)

  • Polycystic kidney disease or renal dysplasia: These are genetic conditions where the kidney(s) do not form correctly and do not function well.

  • Kidney stones

  • Trauma: Inflammation or trauma to the kidneys or ureters can lead to blood in the urine.

  • Neoplasia: Specifically renal lymphoma, which is one of the most common kidney cancers in cats.

  • Infection: Bacteria can invade the kidneys, causing a condition called pyelonephritis. Some viruses (including feline leukemia) can lead to renal lymphoma or a type of cancer of the kidneys leading to inflammation and infection.

  • Chronic kidney disease

  • Idiopathic causes: This refers to inflammation of the kidneys or ureters not caused by bacteria, viruses, neoplasia, or trauma (the reason is unknown).

Lower urinary tract (including the bladder and urethra, also the prostate and penis in male cats and the vulva in female cats)

Other possible causes:

  • Chemotherapy: Certain types of chemotherapeutic drugs can cause sterile inflammation of the bladder, leading to blood in the urine.

  • Estrus: A female unspayed cat that is going through heat can show blood in the urine; this is normal.

  • Clotting abnormalities: Rat poison ingestion, immune-mediated diseases (such as thrombocytopenia), or genetic causes of clotting deficiencies can all lead to bright red blood in the urine.

  • Vasculitis: Leaky blood vessels due to inflammation can lead to blood in the urine.

How Veterinarians Diagnose the Cause of Blood in Cat Urine

A detailed history of your cat’s symptoms, previous medical issues, and any current medications as well as a thorough physical examination are the first steps in diagnosis of hematuria. History alone can help your veterinarian determine what could be causing your cat’s clinical signs. It is important to tell your vet of any supplements or food that you are giving your cat, as some of these can interfere with urine testing.

Full bloodwork and urine testing are often the first diagnostic tests recommended when diagnosing hematuria. Abdominal radiographs and abdominal ultrasound are also often used to further assess the urinary tract for any stones or malformations.

Sometimes cystoscopy is recommended, which is where a small video camera/biopsy instrument is put into the urethra and bladder to check the lining of these organs. If masses are seen, a biopsy can be done for definitive diagnosis. 

Treatment for Cats That Are Peeing Blood

Treatment of hematuria depends on the underlying cause. When a male cat becomes blocked and cannot urinate, unblocking their urethra under sedation is necessary. This requires hospitalization, often for one or two nights, to monitor urination. Some urinary tract stones can be dissolved with prescription diet changes while others require surgical removal. Surgery often requires at least one to two nights in the hospital for pain control and close monitoring.

Urinary tract infections are treated with antibiotic therapy, which is often decided by a urine culture and additional testing. These do not usually require hospitalization. Kidney infection that causes elevations in kidney enzymes or severe dehydration often requires hospitalization with fluid therapy and intravenous antibiotics for several days.

Cancer often requires surgery, radiation, or chemotherapy for remission or improvement. Systemic diseases such as chronic kidney disease will need management and therapy with fluids, diet changes, and often supplements. These systemic diseases require diagnosis and therapy to clear up the blood in the urine, and hospitalization depends on how bad the symptoms are.

The most common cause of blood in the urine in cats, FIC, is treated in several ways. Decreased stress in the environment is the most important point of therapy, since stress is the major cause of this condition. Fluid therapy, pain medications, anti-spasm medications for the urethra, and sometimes behavior modification medications are used for treatment of this condition. 

Unfortunately, even with the proper therapy, blood can continue or recur in the urine. If this occurs, lifelong management changes may be necessary and will need to be discussed with your veterinarian.

Preventing Blood in Cat Urine

Hematuria prevention is tailored to the underlying cause. Any cat with urinary tract issues, especially if they are frequent and recurring, can be helped with environmental and diet changes.

Low-Stress Environment

Cats with FIC need to be in a low-stress environment. Giving your cat a quiet room to stay in, their own food and water bowls, and their own litter box and toys are all helpful if they are experiencing anxiety. The rule of thumb should be one litter box per cat and an additional litter box in the household (for example: if you have three cats, you should have four litter boxes).

Encourage Play

High perches and plenty of stimulating toys can be helpful to reduce stress levels in the home. Keeping litter boxes and beds away from loud machines such as clothes dryers or dishwashers  is also helpful, along with keeping the litter boxes and beds clean. Cats are neat animals and they can get stressed out by a dirty litter box.


It is important to ensure that your cat is eating a well-balanced cat food based on their life stage. Cats with urinary tract inflammation are often eased onto prescription diets that can help maintain a normal urine pH. These include:

Canned food is also preferred over dry kibble because of its higher moisture content.

Water Intake

Improving overall water intake is helpful in lessening hematuria or urinary tract signs. Adding several bowls of fresh water around the house, a water fountain, or even adding water to the food can increase water intake. The goal is proper hydration to lower the urine concentration. This makes for an environment that is less prone to crystal formation, stone formation, and even some bacteria.


Urinary tract probiotic supplements can also be helpful when used in cats with frequent infections, stones, crystals, or idiopathic FIC. These include:

There is new litter made of silica gel on the market that can help determine underlying issues with your cat’s urine. One specific brand, Pretty Litter®, changes color depending on the pH of the urine and if blood is noted.

If you notice blood in your cat’s urine, bring your cat to a veterinarian. Blood in urine is almost never considered normal and can sometimes be an indicator of serious medical issues. The sooner your cat is checked, the sooner testing and treatment can be started to help your cat feel better.

Featured Image:

Katie Grzyb, DVM


Katie Grzyb, DVM


Dr. Katie Grzyb received her Doctorate of Veterinary Medicine from Ross University in 2009. She continued her clinical training at...

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