Bloody mucus in a dog’s urine can be alarming. The combination of blood and mucus often signals irritation in the urinary tract, and it’s not something you want to ignore.
We outline the common causes of bloody mucus in a dog’s urine, what you can do at home, and when to seek veterinary help.
Bloody Mucus in Dog Urine: Why It Happens
Bloody mucus in dog urine happens when the urinary tract becomes inflamed or irritated, causing the bladder or urethra to shed blood and mucus into the urine. Infections, bladder stones, prostate issues, and kidney inflammation are some of the most common reasons for these symptoms, and each of them disrupts the normal protective lining of the urinary system.
Dogs may strain to urinate, seem uncomfortable, or pass only small amounts of urine because inflammation makes urination painful and difficult.
Sometimes the blood appears first and the mucus develops later as the irritation worsens, making early detection important for proper treatment.
Bloody Mucus in Dog Urine: Common Causes
Urinary Tract Infection (UTI)
A urinary tract infection is one of the most frequent causes of bloody mucus in dog urine.
When bacteria enter the bladder or urethra, they irritate the delicate lining and trigger inflammation. This inflammation can cause tiny blood vessels to rupture, which leads to blood mixing into the urine.
As the bladder lining becomes more irritated, the body also produces mucus in an attempt to protect itself, which is why the urine may look stringy, cloudy, or jelly-like.
Dogs with a UTI often urinate more frequently, may strain to pee, and might seem uncomfortable when trying to go outside.
Some dogs leak urine indoors because they cannot hold it. Even mild UTIs should be taken seriously because untreated infections can travel upward to the kidneys.
Read more: Dog Pooping Mucus and Acting Normal (Common causes explained)
Bladder Stones
Bladder stones can cause swelling, irritation, and direct scraping of the bladder wall, which easily leads to bloody mucus in dog urine.
These stones form when minerals accumulate and harden inside the bladder. As they grow, they rub against the bladder lining, damaging tissue and triggering mucus production. Some stones are smooth, while others have sharp edges that can cause repeated injury.
Dogs with bladder stones may squat for longer, attempt to urinate but only release a few drops, or appear restless because of discomfort. Certain breeds, especially Bulldogs, Dalmatians, Miniature Schnauzers, and Shih Tzus, have higher genetic risks.
If stones obstruct the urinary opening, this becomes an emergency, especially for male dogs who have narrower urethras.
Kidney Infection
A kidney infection occurs when bacteria move from the bladder upward into the kidneys, causing serious inflammation.
Kidney infections often produce blood in the urine, and mucus may appear as the urinary system attempts to protect itself from irritation. Because the kidneys filter waste from the blood, any infection there can significantly disrupt normal urine production.
Dogs with pyelonephritis may show additional symptoms such as fever, vomiting, back pain, reduced appetite, or lethargy. The urine may have a strong odor, darker color, or thicker consistency.
Kidney infections are more serious than lower urinary infections and usually require prompt veterinary care and longer courses of antibiotics.
Prostatitis (in Male Dogs)
In male dogs, an inflamed prostate can compress the urethra and interfere with normal urine flow.
Prostatitis—often caused by infection or hormonal changes—can result in bloody mucus in dog urine because the swollen prostate increases pressure on the urinary tract.
This pressure causes irritation, inflammation, and sometimes secondary infections, all of which contribute to blood and mucus production.
Affected dogs may strain to urinate or defecate, leak blood-tinged fluid from the penis, or seem uncomfortable when sitting. Older, unneutered male dogs are at especially high risk.
Early diagnosis is important because untreated prostatitis can lead to abscesses or systemic infections.
Trauma or Irritation to the Urinary Tract
Any injury or irritation to the urinary system can trigger bloody mucus in the urine.
Common causes include rough play, being hit by a vehicle, vigorous scratching at the genital area, or irritation from stones or infections. Trauma can damage the urinary lining, causing bleeding and triggering a protective mucus response.
Even minor injuries may cause visible changes in urine appearance, and dogs may lick the area excessively or behave differently when trying to urinate.
If trauma is suspected, veterinary assessment is recommended because internal injuries are not always obvious.
Tumors or Polyps in the Urinary Tract
Growths inside the bladder or urethra can cause persistent bleeding and excess mucus production.
These tumors—whether benign or malignant—interfere with normal urine flow and irritate the lining of the urinary tract, leading to ongoing inflammation.
Tumors may cause subtle symptoms at first, such as occasional blood in the urine, before progressing to thicker, mucus-filled blood.
Older dogs, especially certain breeds like Scottish Terriers, are more susceptible to bladder tumors.
Early detection improves treatment options and comfort for the dog.
Read more: Dog Mucus in Urine and Diarrhea (What it means)
What to Do If Your Dog Has Bloody Mucus in Their Urine
If you notice bloody mucus in your dog’s urine, stay calm but take the situation seriously.
Start by observing your dog’s behavior while urinating. Pay attention to whether they strain, produce only a few drops at a time, pace nervously, or appear uncomfortable. These details will help a veterinarian identify the underlying problem quickly.
Offer plenty of fresh water to keep your dog hydrated. Water helps flush bacteria from the bladder and dilutes the urine, which may reduce discomfort. Avoid restricting water intake, as dehydration makes urinary symptoms worse.
If possible, collect a clean urine sample. Using a shallow container or ladle can make this easier. Bringing a sample to the vet can speed up diagnosis because testing can begin immediately, even before your appointment.
Keep your dog from licking the genital area excessively, as this can introduce bacteria and worsen irritation. If necessary, use a soft cone to discourage licking until you reach the veterinarian.
Avoid giving any human medications or leftover antibiotics, as these may be harmful or mask symptoms, complicating diagnosis.
When to Call or Visit Your Vet
Seek veterinary attention promptly if your dog continues to pass bloody mucus in urine or if the symptoms worsen.
If your dog strains repeatedly without producing urine, this may indicate a blockage. Urinary blockage—especially in male dogs—is an emergency that can quickly become life-threatening.
Contact your vet immediately if you see signs like fever, vomiting, lethargy, back pain, or refusal to eat. These symptoms may signal a kidney infection or a more advanced condition.
If you suspect your dog has bladder stones, prostatitis, or trauma to the urinary tract, schedule an appointment as soon as possible. These issues can escalate quickly without treatment.
Persistent blood or mucus in the urine always warrants a veterinary exam, even if your dog seems comfortable. Early intervention prevents complications and reduces pain.
Related: Mucus in female dog urine (What it means)
Key Takeaway
Bloody mucus in dog urine is a sign that the urinary tract is irritated, inflamed, or battling an infection. While some causes are simple to treat, others require prompt medical attention to prevent serious complications.
Paying close attention to your dog’s urination habits, keeping them hydrated, and seeking veterinary help when symptoms persist will give your dog the best chance at quick relief and recovery.
If you ever notice blood or mucus in your dog’s urine, trust your instincts and reach out to your veterinarian. Early care can make a significant difference in your dog’s comfort and overall health.