Urinary Tract Infection

• Just like humans, dogs can suffer from infections in the urinary tract, which sometimes lead to blood being present in the urine. Bacteria travel up the urethra, which is the tube through which urine exits the body, and infect the bladder. In some cases, the infection spreads to the kidneys. A urinary tract infection may not be serious and could resolve by itself, but if it does not it can worsen and lead to uncomfortable symptoms such as blood in the urine, urination in inappropriate places, the dog straining to urinate and a foul smell from the urine.
  
  

Stones

• Another possible cause for blood in the urine of dogs is stones in the kidney or bladder. These stones are formed out of the natural minerals that occur in the urine, which have crystallized to form a hard rock. The symptoms of a bladder stone include blood in the urine and more frequent urination, with the dog passing only very small amounts of urine each time. Kidney stones can also cause blood in the urine and, if the stones begin to move out of the kidney and toward the bladder, abdominal pain and straining during urination.
  
  

Poisoning or Injury

• Some of the causes of blood in the urine may be external events such as the dog being in an accident that has led to internal bleeding or eating rat poison. The anticoagulant medication Warfarin sometimes is used to poison rats, but if a dog eats these pellets it could suffer from internal bleeding and start losing blood in its urine. It is important to get a dog to a vet if poisoning is a possibility because the results could be fatal.
  
  

When to See a Vet

• In all cases in which a dog has blood in its urine, it is advisable to see a vet and have the cause of the problem verified. There are some less common problems that could lead to your dog's illness, including serious issues such as cancer that a professional needs to check for when examining your pet.