The short answer
Blood in the urine is usually caused by urinary infections, kidney stones, or an enlarged prostate — not cancer. But because it can be an early sign of bladder or kidney cancer, any blood in the urine, even once, should be checked by a doctor.
Most blood in the urine comes from infections, stones, or an enlarged prostate.
Because it can be an early sign of bladder or kidney cancer, it should always be checked.
Blood may be visible or found only on a urine test.
Even a single episode of visible blood in the urine is worth a doctor's review.
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The full explanation.
The simple version
Blood in the urine (doctors call it hematuria) looks alarming, but it is most often caused by common problems — urinary tract infections, kidney stones, vigorous exercise, or an enlarged prostate. Even so, because it can be an early sign of bladder or kidney cancer, it is always worth checking.
What usually causes it
Urinary infections are the most common cause, often with burning or needing to go often. Kidney or bladder stones, an enlarged prostate in older men, and even hard exercise can also cause it. Some foods and medicines can turn urine red without any blood at all.
Why it is still worth checking
Bladder and kidney cancers can show up first as painless blood in the urine, sometimes coming and going. Because these cancers are far more treatable when found early, doctors take even a single episode of visible blood in the urine seriously — not to alarm you, but to rule things out.
When to see a doctor
See a doctor about any visible blood in the urine, even once and even if it goes away. Get checked sooner if it comes with pain, fever, or trouble urinating. Simple urine tests and, if needed, a scan can find the cause.
Words to know
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Common questions
▸Does blood in the urine mean cancer?
Usually not. It is most often caused by infections, stones, or an enlarged prostate. But because it can be an early sign of bladder or kidney cancer, it should always be checked.
▸It happened once and stopped — do I still need to get it checked?
Yes. Even a single episode of visible blood in the urine is worth a doctor's review, because bladder and kidney cancers can cause bleeding that comes and goes.
▸What are the common non-cancer causes?
Urinary tract infections, kidney or bladder stones, an enlarged prostate, and vigorous exercise are common causes. Some foods and medicines can also color the urine.
▸Is painless blood more concerning?
Painless visible blood in the urine is a classic reason to get checked, but any blood in the urine is worth reviewing regardless of pain.
Questions to ask your doctor
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