You went to the bathroom and the water in the bowl looked pink, red, or even cola-colored. It's an alarming thing to see, and your mind probably jumped straight to the worst case. Take a breath. Blood in the urine, called hematuria, is common and has a long list of possible causes, many of them very treatable.
Here's the honest part, though: blood you can see should always be checked by a clinician, because the same symptom can signal something minor or something that needs prompt attention. This guide walks through the most common causes, the difference between blood you can see and blood you can't, and how to know when it's time to call a doctor.
What does blood in urine (hematuria) actually mean?
Hematuria simply means red blood cells are showing up in your urine. Doctors split it into two types. Gross hematuria is blood you can actually see, turning the urine pink, red, or brown. Microscopic hematuria is blood that's only detectable under a microscope during a urinalysis, often found by chance during a routine checkup.
The amount of blood doesn't reliably tell you how serious the cause is. Even a tiny amount can tint urine, and a small bleed you can't see at all may still matter. That's why the type and pattern of bleeding, not just the color, guide how it gets evaluated.
One important caveat: red or brown urine isn't always blood. Foods like beets and rhubarb, and certain medications, can change urine color without any bleeding at all. A simple urine test can sort out which is which.
What are the most common causes of blood in urine?
Most cases trace back to the urinary tract: the kidneys, ureters, bladder, urethra, and (in men) the prostate. Causes range from very common and benign to rare and serious. Common, usually treatable culprits include:
- Urinary tract infections (UTIs), which often come with burning, urgency, or cloudy urine
- Kidney stones or bladder stones, which can cause sharp pain as they move
- An enlarged prostate (benign prostatic hyperplasia, or BPH) in older men
- Vigorous exercise, which can briefly cause bleeding that clears on its own
- Sexual activity, and in some people, endometriosis
- Certain medications, including blood thinners (like aspirin and heparin), some antibiotics (such as penicillin), and pain relievers
When is blood in urine a sign of something serious?
A smaller share of cases point to conditions that need timely care. These include cancers of the bladder, kidney, or prostate, glomerular kidney disease (where the kidney's filtering units are inflamed), and inherited conditions such as sickle cell disease and certain blood-clotting disorders like hemophilia.
This is why visible blood gets attention. Gross (visible) hematuria is more strongly associated with urinary tract cancer than microscopic hematuria, which carries a lower risk. Visible bleeding doesn't mean you have cancer, most people who experience it don't, but it does warrant a prompt evaluation rather than a wait-and-see approach.
Reassuringly, risk is heavily stratified. In a large study evaluating the American Urological Association's 2020 risk classification, cancer detection in the low-risk group was approximately 0.4%, compared with about 6.3% in the high-risk group. Factors like your age, sex, smoking history, and how much and how often you're bleeding shape how likely a serious cause is and how aggressively it's evaluated.
How common is hematuria, and how is it defined?
Blood in the urine is more common than many people realize. According to the NIH, at least 1 out of 5 people evaluated by a urologist is diagnosed with hematuria. Among healthy volunteers, microscopic hematuria prevalence has been reported anywhere from 2.4% to 31.1%, depending on the population studied.
Clinically, microhematuria has a precise definition: 3 or more red blood cells per high-power field on a single, properly collected urine sample, per the AUA/SUFU 2020 guideline. That standard helps doctors decide when a finding is worth investigating further rather than dismissing or over-testing.
Sometimes, even after a full workup, no clear cause is found. That can be reassuring, but your clinician may still recommend follow-up testing depending on your risk factors.
How is blood in urine diagnosed and treated?
Evaluation usually starts with a urinalysis to confirm real blood and check for signs of infection. From there, testing is tailored to your risk profile and may include urine studies, blood tests, imaging of the kidneys and bladder, or a cystoscopy (a thin scope that looks inside the bladder).
Treatment depends entirely on the cause. A UTI is typically treated with antibiotics, which usually begin easing symptoms within a day or two. Kidney stones may pass on their own or need a procedure. An enlarged prostate has its own range of medical and procedural options. More serious causes are managed by the appropriate specialist. The key point: hematuria is a symptom, not a diagnosis, so the goal is always to find and treat what's behind it.
When should you see a doctor?
Any time you can see blood in your urine, get evaluated, even if it happens once and then stops. Don't wait for it to come back. Also reach out promptly if microscopic blood was flagged on a routine test, as your clinician will decide whether follow-up is needed.
Seek urgent or emergency care if blood in the urine comes with severe pain, a high fever, an inability to urinate, or passing large clots, and call your doctor right away if heavy bleeding follows an injury. While many causes are harmless, a clinician is the only one who can tell the minor from the serious, and for most causes, catching things early leads to easier treatment.
Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider before starting any new skincare treatment, especially if you have underlying health conditions, are pregnant, or are taking medications.
