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why would i have blood in my urine

Blood in urine (called hematuria) can come from many different causes, ranging from minor and easily treated to serious and urgent, so it always deserves medical attention, especially if it’s new, persistent, or heavy. Because some causes can be emergencies (like infection, stones, or cancer), seeing a doctor or urgent care promptly is very important if you notice red, pink, or cola- colored urine, clots, pain, or feel unwell.

What “blood in urine” really means

  • Hematuria means red blood cells are present in your urine, either visible (urine looks red, pink, or cola-colored) or only seen on a urine test (microscopic hematuria).
  • It can come from anywhere in the urinary tract: kidneys, ureters, bladder, prostate (in people with a prostate), or urethra.

Even if the urine just “looks red,” it is treated as possible blood until a doctor proves otherwise, because food dyes and some foods (like beets) can also change urine color.

Common causes (from less to more serious)

Here are some of the more frequent reasons someone might ask, “why would I have blood in my urine?”

  • Urinary tract infection (UTI)
    • Burning or pain when peeing, going very often, urgency, lower belly discomfort, sometimes fever or feeling generally sick.
* Blood can appear because the bladder or urethra lining is inflamed and irritated.
  • Kidney or bladder stones
    • Sudden severe flank or side pain, pain that comes in waves, pain down into the groin, nausea/vomiting, and blood in urine.
* Stones can scrape or block parts of the urinary tract, causing bleeding and sometimes infection.
  • Inflammation of the bladder or kidneys
    • Conditions like cystitis (bladder inflammation) or glomerulonephritis (inflammation of the kidney’s filtering units) can cause blood, swelling, and sometimes high blood pressure or foamy urine.
  • Enlarged prostate (BPH) or prostate issues
    • In people with a prostate, difficulty starting urination, weak stream, dribbling, getting up at night to pee, sometimes blood in urine.
* Both benign enlargement and prostate cancer can present with hematuria in older adults.
  • Cancer of bladder, kidney, or prostate
    • Can cause painless visible blood in the urine, especially in adults over 35–40, sometimes with weight loss, fatigue, or urinary changes.
* Because cancers may not cause other symptoms early on, new blood in urine in adults usually needs imaging and a specialist check.
  • Exercise-related hematuria
    • Vigorous or long-distance exercise (for example, marathon running) can cause temporary blood in urine that often clears when activity stops.
* Even though it can be benign, other causes must be ruled out, especially if it recurs.
  • Injury/trauma
    • A fall, car accident, or direct blow to the back or abdomen can damage the kidneys or urinary tract and cause visible blood.
* This is treated as urgent, particularly if there is pain, dizziness, or low blood pressure.
  • Medications and medical conditions
    • Some blood thinners (like those affecting clotting), certain antibiotics, and chemotherapy drugs can be associated with hematuria.
* Blood-clotting disorders, sickle cell disease, and inherited kidney diseases (like polycystic kidney disease or glomerular diseases) can also lead to blood in urine.
  • Gynecologic and menstrual factors (for people who menstruate)
    • Blood from menstruation can mix with urine in the toilet or sample and falsely look like hematuria.
* Endometriosis affecting the urinary tract can cause cyclical blood in urine around the time of the period.

When it’s an emergency

Seek urgent or emergency care (same day, ER if needed) if any of these are happening with blood in your urine:

  • You see large amounts of blood, clots, or the urine looks like pure blood.
  • You have fever, shaking chills, flank or back pain, nausea/vomiting, or feel very unwell (possible kidney infection or severe UTI).
  • You have severe side or lower back pain that comes in waves, with sweating or vomiting (possible stone or blockage).
  • You recently had an injury to your back, side, or abdomen and now see blood in urine.
  • You have trouble peeing at all, new incontinence, or can only pass a few drops despite feeling very full.

If it is not severe but is new, persistent, or if you are over about 35–40 years old, it still needs prompt non-emergency evaluation because cancers and other serious conditions are more common with age.

What doctors usually do next

Health professionals look at both your story and tests to work out why there is blood in your urine.

  • Questions you’ll likely be asked
    • When you first noticed the blood, whether it hurts, how often it happens, and any fever, weight loss, flank pain, or urinary changes.
* Past UTIs, stones, surgeries, smoking history, family kidney disease, and medicines (including blood thinners).
  • Common tests
    • Urinalysis and urine culture to look for blood, infection, protein, or crystals.
* Blood tests for kidney function and sometimes clotting tests or other markers.

* Ultrasound, CT scan, or other imaging to look at kidneys, ureters, and bladder; sometimes cystoscopy (a camera into the bladder) to look directly at the lining.
  • Treatment depends on the cause
    • Antibiotics for bacterial infections, pain medication and sometimes procedures for stones.
* Specific treatments for prostate problems, kidney disease, blood disorders, or cancer if found.

What you should do right now

Because this is a potentially serious symptom and the exact cause depends heavily on your age, sex, medical history, and any other symptoms, it is not safe to self-diagnose.

  • If you are currently seeing visible blood in your urine, especially with pain, fever, or feeling faint, treat it as urgent and seek in-person care as soon as possible.
  • If it happened once but stopped, still arrange a timely appointment with a primary care doctor or urologist; even one episode can be important to check.
  • Do not start or stop prescription medications on your own; discuss all medicines and supplements with your clinician.

This information is general and not a diagnosis. Only a clinician who evaluates you in person and reviews your tests can tell you why you personally have blood in your urine.

Information gathered from public forums or data available on the internet and portrayed here.