Blood in Your Urine: Causes You Shouldn't Ignore

Cardio Renal Foundation is a 501(c)(3) tax-exempt charity organization. Your donation advances our mission to provide a solution beyond dialysis.

Noticing blood in your urine can be alarming. Urine is not supposed to look pink, red, or brown. Sometimes the cause is minor and temporary. Sometimes it needs prompt attention. The important point is simple: any visible blood in urine should be evaluated promptly, even if it happens only once and even if it goes away on its own.

This guide explains hematuria — the medical term for blood in the urine — in plain language: its two forms, what colors can and cannot tell you, the causes doctors consider, and what happens when you get it checked. It cannot tell you why it is happening in your case — only an evaluation can.

What Is Hematuria? Visible and Microscopic Blood

Hematuria simply means red blood cells are present in the urine. Doctors describe it in two forms:

Gross hematuria is blood you can see. The urine may look pink, red, cola-colored, or tea-colored, and there may be visible blood clots. It does not take much blood to change urine color noticeably, so a dramatic color does not necessarily mean a large amount of blood — but visible blood always deserves a prompt conversation with a doctor.

Microscopic hematuria is blood that cannot be seen. The urine looks normal, and the blood cells are found only when a laboratory examines urine under a microscope or a dipstick test flags them. It is often found by chance during a urinalysis done for another reason. Doctors still take it seriously and usually recommend follow-up, because it can be an early clue to a problem in the urinary tract or kidneys.

What Can Urine Color Tell You — and What Are the Look-Alikes?

Color can offer a general hint, but it is never a diagnosis. Pink or bright red urine suggests fresh blood somewhere in the urinary tract. Brown, tea-colored, or cola-colored urine can suggest blood coming from higher up, including the kidneys — but color alone cannot pinpoint a source. Cloudy urine or discomfort while urinating can raise questions about infection, yet those signs can occur with or without blood.

It also helps to know that not everything that turns urine red is blood. A few well-known look-alikes include:

• Certain foods: Beets, blackberries, and rhubarb can tint urine pink or red in some people. It is harmless and fades as the food leaves your system.
• Certain medicines and vitamins: Some medications — including certain antibiotics and laxatives — can change urine color to red, orange, or brown, as can some supplements.
• Vigorous exercise: Very hard or prolonged exercise, such as long-distance running, can occasionally cause temporary blood in the urine.

The catch is that you cannot reliably tell a look-alike from real blood just by looking. A simple urine test can. If a color change is new, unexplained, or keeps happening, get it checked rather than guessing.

What Can Cause Blood in the Urine?

Blood can enter urine anywhere along its path — the kidneys, the tubes carrying urine to the bladder, the bladder, and the urethra. In men, the prostate sits close to that path and can be involved as well. In general terms, causes doctors consider include:

• Urinary tract infection (UTI): Bacteria infecting the bladder or urinary tract can irritate its lining and cause blood, often alongside burning or urgency.
• Kidney or bladder stones: Hard mineral deposits can scrape the lining of the urinary tract as they move, causing blood, sometimes with pain in the side, back, or groin.
• Prostate enlargement: In men, an enlarged prostate — very common with age — can cause blood in the urine, along with a weaker stream.
• Vigorous exercise: Strenuous activity occasionally causes temporary hematuria that clears within a day or two, though doctors generally still want to confirm that rather than assume it.
• Kidney disease or inflammation: Conditions that inflame or damage the kidneys' filtering units can allow blood cells to leak into the urine, often in microscopic amounts.
• Injury: A blow to the kidneys or urinary tract — from an accident or fall — can cause visible blood.
• More serious conditions: Stated plainly and without alarm: blood in the urine can sometimes be a sign of a more serious condition, including cancers of the bladder, kidney, or prostate. That is not a reason to panic, because most cases of hematuria are not caused by cancer. It is, however, exactly why unexplained blood should always be checked.

This list describes possibilities in general, not probabilities in your case. Age, health history, other symptoms, and test results all shape what a doctor considers most likely.

Why "It Went Away" Doesn't Mean It Can Be Skipped

One common reason people delay care is that the blood disappears. The urine looks normal the next day, so it is easy to assume the problem solved itself. That logic does not hold. Many causes of hematuria — including some serious ones — bleed intermittently. Bleeding can stop and start again weeks or months later while the underlying cause is still there.

Think of visible blood as a warning light. One that turns off has still told you something happened, and the sensible response is to have it looked at while finding the cause is easiest. A single episode, even one that never returns, is worth reporting.

What Does a Doctor Typically Do to Find the Cause?

An evaluation usually begins with conversation and a urine test, and builds from there. A typical workup may include:

• Your history and an examination: Your doctor will likely ask when you noticed the blood, whether you have pain, fever, or other symptoms, what medicines you take, and whether you have had infections, stones, or kidney problems before.
• Urinalysis: A laboratory examines your urine to confirm that what is present really is blood, and to look for signs of infection, protein, or other clues. A urine culture may also check for bacteria.
• Blood tests: Blood work can check how well the kidneys are filtering, including measurements such as creatinine and eGFR.
• Imaging: An ultrasound or CT scan can picture the kidneys, bladder, and urinary tract, helping doctors look for stones or growths.
• Referral to a specialist: You may be referred to a urologist, who specializes in the urinary tract, or a nephrologist, who specializes in the kidneys. A specialist may recommend a closer look inside the bladder with a thin camera, called cystoscopy, when the situation calls for it.

Not everyone needs every test. The goal is straightforward: find where the blood is coming from and why, so the cause can be addressed directly.

When Should You Get Help Promptly?

Any visible blood should be evaluated promptly — contact your doctor or seek care the same day rather than waiting to see whether it happens again. Some situations warrant urgent care right away:

• Blood with pain or fever: Blood together with fever, chills, or pain in the side, back, or abdomen can suggest infection or a stone needing timely attention.
• Visible blood clots: Passing clots is a sign of heavier bleeding and should be assessed right away.
• Inability to urinate: If you cannot pass urine despite feeling the urge, seek urgent care.
• Blood after an injury: Blood after a blow to the back, side, or abdomen, a fall, or an accident should be checked urgently, even if you feel fine.
• Heavy or ongoing bleeding: Urine that stays deep red should not wait.

If you are unsure how urgent your situation is, err on the side of calling.

A Symptom Worth Taking Seriously — Calmly

Blood in the urine is common, its causes range from minor to serious, and no article can tell you which applies to you. The symptom is a signal, and signals deserve investigation. If you have noticed blood in your urine — visible or reported on a lab test — bring it to your doctor's attention promptly and let the evaluation do its work.

Blood in the urine is a sign that deserves a doctor, promptly — and behind individual scares like this one sits a population of kidneys quietly failing. The Cardio Renal Foundation supports research toward that larger picture: a future beyond dialysis, including ways to remove excess fluid without a machine. This article handles the alarm in front of you; that research is aimed at the epidemic behind it.

At the Cardio Renal Foundation, we believe plain-language education like this is a genuine first line of defense, and support from readers like you helps us keep publishing it for the patients and families who need it.

This article is informational only and is not meant to replace the advice of your qualified healthcare provider. As with any issues related to your health, check with your doctor.