Why Is There Blood in My Dog's Urine?

Blood in a dog's urine (hematuria) is never normal and always warrants veterinary investigation, but it's rarely a life-threatening emergency in an otherwise well dog. The most common cause is a urinary tract infection (UTI), which is easily treated with antibiotics.

In female dogs, first determine whether the blood is actually in the urine or coming from the vulva. Intact (not spayed) females may have bloody vaginal discharge during their heat cycle, and spayed females can have vaginitis. Wiping the vulva and watching where the blood comes from can help clarify.

Urinary tract infections (UTIs) are the most common cause in both sexes but are more prevalent in females due to their shorter urethra. Signs include frequent urination, straining to urinate, urinating small amounts, blood-tinged urine, and sometimes urinating in unusual places.

Bladder stones (uroliths) can cause bloody urine along with straining and frequent urination. Some breeds are predisposed to specific stone types. Small stones can sometimes pass on their own, but larger ones may require surgical removal or dietary dissolution.

In intact male dogs, prostate disease (enlargement, infection, or cancer) commonly causes bloody urine. In older dogs of either sex, bladder tumors (transitional cell carcinoma) should be considered, especially in terrier breeds.