10 Causes of Blood in Urine

Blood in the urine, or hematuria, refers to the presence of red blood cells in the urine. The causes range from completely benign to life threatening, so if you notice this symptom be sure to have it checked out by your doctor. Visible blood in the urine (macroscopic hematuria) may cause the urine to appear pink, red, or cola colored, although there may be blood present that is not visible to the naked eye that can only be seen using a microscope or detected using a special dipstick test (microscopic hematuria).

If your urine appears to have blood in it, keep in mind that some highly pigmented foods, such as beets and berries may cause your urine to change color. This should go away in a few days, and is not a cause for concern. Similarly, certain medications such as some laxatives, antibiotics and chemotherapy drugs may also cause a change in the color of your urine. So the first thing you should do if you notice “bloody urine” is to consider whether or not you have ingested something that may have caused a color change—there may not even be blood in your urine after all!

If there is in fact blood in your urine, one of the following may be the cause:

1) Urinary Tract Infection (UTI)

UTIs are the most common cause of blood in the urine, particularly in women. They may be accompanied by pain and difficulty passing urine, urinating more frequently, pain in the abdominal area, and fever. Fortunately, most UTIs are effectively treated with a short course of antibiotics. You can prevent UTIs in the future by remaining well hydrated and passing urine often—don’t hold it up! By doing this, bacteria are flushed out before they get a chance to cause infection. Additionally, when using the restroom take care to wipe from front to back to reduce spreading bacteria from the anus to the urethra. And finally, always urinate after sex so that any bacteria that entered the urinary tract is pushed back out.

Blood in Urine

2) Kidney Infection

Kidney infections (pyelonephritis) can occur following an untreated UTI. The symptoms of a kidney infection are similar to those of a UTI though they may be more severe, and often accompanied by back pain on the side of the affected kidney. The treatment involves a longer course of antibiotics, which may need to be given intravenously in hospital, depending on the severity of the infection. Kidney infections require urgent treatment as left untreated, the kidney may be permanently damaged or the bacteria may spread to the bloodstream, leading to septicemia (infection of the blood), which is a life threatening condition.


Kidney stones (nephrolithiasis) are solid deposits that form in the kidneys. They can be found in any part of the urinary tract and may be extremely painful. In fact, the pain of passing a kidney stone has been compared to the pain of childbirth! are often composed of calcium or uric acid and vary in size. You are more likely to get kidney stones if you are not well hydrated, as stones are more likely to form in very concentrated urine.

Many stones will pass on their own, however, if a stone does not pass on its own, there are medical procedures that can be performed to either remove it, or break it into smaller pieces so that it passes on its own. Having a kidney stone once means that you are at a higher risk of having one again in the future. To prevent this, your doctor may give you a prescription medication and/or suggest dietary changes to lower your odds of stones recurring.

4) Exercise Induced Hematuria

Also called “Runner’s Bladder”, this benign condition occurs following bouts of exercise. If the urine clears within 72 hours of exercise there is no need to do further investigation. Athletes may return to play if the hematuria has resolved within this time period. 

In most cases of exercise-induced hematuria, there is a direct relationship with the intensity of the activity, the duration of the activity, and the level of hydration of the athlete. This is especially true in the case of extended endurance events (such as marathons) and weight-bearing intense activities (such as power-lifting).  Exercise can also cause direct impact to kidneys, the bladder or urethra, all of which can lead to traumatic hematuria.

 Exercise-induced hematuria is not normally accompanied by additional symptoms, however if as a result of direct impact, pain at the site of impact is to be expected. Treatment depends on the severity of trauma after the 72 hours have elapsed. It is recommended that athletes engaging in prolonged, intense activity be sufficiently hydrated and wear the necessary protective equipment.

5) Glomerulonephritis

Glomeruli are microscopic clusters of blood vessels within the kidneys which filter blood through small pores. Glomerulonephritis is an inflammation of these tiny filters which may be caused by an autoimmune disorder, blood vessel inflammation (vasculitis), genetic disorder or various types of infection. As more glomeruli become damaged, there is greater tissue damage and loss of kidney function. Signs and symptoms include high blood pressure, fluid retention (edema) and red blood cells present in the urine. Treatment of glomerulonephritis depends on the underlying cause, so it is important to see your doctor if you have concerning symptoms.

6) Polycystic Kidney Disease

Polycystic Kidney Disease is a rare genetic condition which causes numerous fluid filled cysts to grow within the kidneys. As the cysts enlarge, they reduce kidney function, eventually causing kidney failure. Blood in the urine is caused by rupture of these cysts or of small blood vessels surrounding the cysts. In addition to blood in the urine, polycystic kidney disease may be accompanied by back or side pain, an enlarged abdomen, frequent UTIs and high blood pressure. Most people will not develop any of these signs and symptoms until they are about 30 to 40 years old. There is currently no cure, but the loss of kidney function can be slowed by careful management of blood pressure, prompt treatment of infections, remaining well hydrated throughout the day, and maintaining a healthy lifestyle.

7) Clotting Disorders

Certain disorders of the blood, for example hemophilia, are associated with blood in the urine. Up to 66% of persons with hemophilia experience hematuria at one point or another. Hemophilia is an inherited bleeding disorder most commonly seen in males, in which the blood doesn’t clot normally. Since clotting is faulty, bleeding may occur spontaneously or following extremely mild injury.

While hemophiliacs generally should receive treatment at the first sign of a bleed, in the case of blood being passed in urine it is important that the exact source of the bleed is pinpointed first as treatment can cause a clot to form, causing an obstruction which may prevent the passage of urine. If a hemophiliac experiences hematuria, he or she should rest and increase his or her fluid intake. If there are no accompanying symptoms to suggest infection and no history of trauma, all that may be needed is rest and fluids. However, if the bleeding persists longer than a few days, a hospital visit may be necessary.

8) Enlarged Prostate

The prostate gland is the part of the male reproductive system responsible for male fertility. Its roles are the transportation and nourishment of sperm through the secretion of semen. Over time, the prostate increases in size (benign prostatic hyperplasia or BPH) and begins to put pressure on the urethra, causing difficulty in urination. This blockage of urination can cause damage to the blood vessels, especially if the bladder becomes overworked, leading to blood in the urine. BPH affects approximately 50% of adult males between the age 51-60 years old. Other BPH symptoms include frequent urination, urgency in the need to urinate, straining while urinating, weak urine flow, difficulty initiating urination and the feeling that the bladder is full at all times. 

BPH should be treated to avoid UTIs, kidney stones, and acute urinary retention. Treatment options are considered based on the size of the prostate, severity of symptoms, age and overall health of the individual as well as any other coexisting medical conditions. Treatment options include alpha blockers (which relax muscles making it easier to urinate), 5-alpha reductase inhibitors (block hormones that cause gland growth), minimally invasive surgeries and invasive surgeries.

9) Tumor in the Bladder, Kidney or Prostate

While most people with blood in the urine do not have cancer, hematuria may be one of the few early warning signs of malignancy of the bladder, kidney or prostate. Therefore it is very important that an episode of blood in the urine be evaluated by your doctor. The earlier you receive treatment, the better your outcome is likely to be. While it is not possible to completely prevent the development of these cancers, you can lower your risk by adhering to a healthy diet and exercise regime and avoiding known risk factors such as smoking and exposure to carcinogens.

10) Medications

While some medications merely cause the urine to appear red, others can actually cause bleeding. Examples include some blood thinners and certain chemotherapy drugs. It is important to discuss with your doctor the potential side effects of any medications you are taking, and what you should do should the side effects occur.