Red Urine: Causes, Blood vs Food, and When to Act
Updated April 2026
See a doctor today if no food explanation
Visible red urine not explained by recent beetroot or berries needs same-day assessment. In the UK: adults over 45 with painless visible blood urine qualify for an urgent two-week GP referral. Do not wait.
The First Question: Did You Eat Beetroot?
Visibly red urine is alarming. Before any investigation, ask one question: did you eat beetroot, blackberries, bilberries, or similar dark red foods in the last 24 hours? If yes, beeturia is the probable explanation. If no, treat this as gross haematuria (visible blood in urine) until proven otherwise, and see your GP today.
This single question matters enormously because the management pathways are completely different. Beeturia needs no treatment other than reassurance; gross haematuria requires medical evaluation to identify the source and rule out serious underlying conditions.
If you are unsure, the safe approach is to stop eating beetroot and check again in 24-48 hours. If the red clears, beeturia was the explanation. If it persists, see your GP. A urine dipstick test at any GP or clinic can confirm whether red blood cells are present in under five minutes.
What Causes Gross Haematuria
Gross haematuria (visible blood in urine) has many causes, most of which are not cancer. The most common are:
1. Urinary tract infection (UTI)
The most common cause, particularly in women. Infection causes inflammation of the bladder lining, and blood vessels can bleed into the urine. Usually accompanied by burning, frequency, urgency, and cloudy urine.
2. Kidney stones
A stone moving through the ureter can scratch tissue and cause significant bleeding. Often accompanied by severe, colicky flank pain (one of the most intense pain experiences reported). May also cause nausea and vomiting.
3. Enlarged prostate (BPH) or prostatitis
In men, a large prostate or inflamed prostate can cause blood in urine. May accompany urinary frequency, hesitancy, or a weak stream.
4. Glomerulonephritis
Inflammation of the kidney's filtering units (glomeruli) can allow blood cells to leak into urine. May follow a throat or skin infection. Can produce cola-coloured or red urine alongside swelling and high blood pressure.
5. Vigorous exercise (athletic haematuria)
Long-distance running can produce red urine from bladder impact trauma (the empty bladder walls hitting each other), or from muscle breakdown (myoglobinuria, though this is usually brown rather than red). Clears within 24-48 hours of rest. Persistent red after exercise should be evaluated.
6. Bladder or kidney cancer
Painless visible haematuria is the most common presenting symptom of bladder cancer. This does not mean it is the likely cause - UTIs and stones are far more common - but it is why any unexplained visible blood needs investigation, especially in people over 45 or with risk factors (smoking history, occupational chemical exposure).
The UK Two-Week Rule for People Over 45
In the United Kingdom, NHS guidelines (NICE NG12, updated 2023) specify that adults aged 45 and over with unexplained visible haematuria - even a single episode, even painless - should receive an urgent cancer pathway referral within two weeks. This is not because bladder cancer is likely; it is because painless visible blood is the most common early symptom and catching it early makes treatment far more effective.
The same guidelines apply to adults under 45 with visible haematuria, though the urgency threshold is slightly different. Any visible blood in urine without a clear benign explanation warrants assessment.
For US readers: the American Urological Association (AUA) recommends that any adult with unexplained gross haematuria undergo evaluation. There is no established age threshold for urgent referral in US guidelines, but current AUA guidance considers any gross haematuria significant.
Rhabdomyolysis: Red-Brown Urine After Extreme Exercise
A specific scenario worth knowing about: brown-to-red urine after extreme physical exertion (marathon running, very heavy weightlifting, military training, or seizures) can indicate rhabdomyolysis - the breakdown of muscle fibres releasing myoglobin, a muscle protein that is toxic to the kidneys at high concentrations.
Rhabdomyolysis-related urine is typically more tea-brown or brown-red than bright red, and occurs alongside severe muscle pain and weakness. This is a medical emergency. If you notice dark red-brown urine after extreme exercise along with severe muscle pain, seek emergency care. See the brown urine page for full detail on rhabdomyolysis.
When to Seek Care
Today / emergency: Red plus severe flank pain, vomiting, fever; red with blood clots; red after crush injury or seizure; red urine in a child with no food explanation.
GP same day: Any visible red urine not explained by recent beetroot or berries. Over-45 in the UK: mention the two-week rule to your GP.
Monitor: Ate large amounts of beetroot or dark berries in the last 24 hours, no other symptoms - stop eating those and check again in 24-48 hours.
Frequently Asked Questions
Should I go to the doctor for red urine?
Yes, if you did not eat beetroot or berries recently. Visible blood in urine requires assessment. In the UK, over-45s with painless visible blood qualify for an urgent two-week referral. This does not mean cancer - UTIs and stones are far more common - but it must be ruled out.
Can red urine be caused by exercise?
Yes, in two ways. First, vigorous running can cause bladder-impact haematuria - red urine that clears with rest within 24-48 hours. Second, extreme exercise can cause rhabdomyolysis (muscle breakdown), producing brown-red urine alongside severe muscle pain - this needs emergency care. If red urine after exercise does not clear in 24 hours, see a doctor.
Is red urine in men different from women?
The evaluation approach is similar, but some causes differ by sex. In women, a UTI is more common; in men, prostate disease and bladder cancer are more common (bladder cancer is 3-4x more common in men). Over-45 guidance applies to both sexes.
What does red urine from a kidney stone look like?
Kidney stone haematuria is usually bright red or pink and occurs alongside very severe, colicky flank pain radiating to the groin. People typically know something is very wrong because the pain of a kidney stone is one of the most intense pain experiences in medicine. If you have severe flank pain and red urine, seek emergency care.
Sources: NHS Blood in Urine; Cleveland Clinic; NICE NG12 urgent cancer referral guidelines.