Brown Urine: Causes, Liver Disease, and Rhabdomyolysis
Updated April 2026
Usually needs same-day GP assessment
Brown or tea-coloured urine has several serious possible causes. Do not simply drink water and wait. See your GP today unless you are on a known medication that causes it (metronidazole, nitrofurantoin) and have no other symptoms.
What Brown Urine Can Mean
Brown or tea-coloured urine sits at the serious end of the colour spectrum. Unlike dark yellow, which almost always responds to drinking water, brown urine persisting after rehydration suggests a substance beyond urochrome is entering the urine - and the candidates include several significant medical conditions.
The three major non-medication causes of brown urine are: severe dehydration (treatable), liver or bile duct disease with bilirubin overflow, and rhabdomyolysis (muscle breakdown releasing myoglobin). The clinical context usually distinguishes them: are you severely dehydrated from an illness? Do you have yellow eyes or right-side abdominal pain? Did you have extreme muscle exertion, a seizure, or a crush injury recently? These questions guide the diagnosis.
Causes of Brown Urine
1. Severe dehydration
When dehydration becomes severe, urochrome concentration can produce a distinctly brown-orange colour. This typically requires prolonged severe fluid restriction, illness with heavy sweating and vomiting, or both. Unlike dark yellow, which lightens quickly with water, brown from severe dehydration requires aggressive rehydration - often with oral rehydration salts if nausea prevents plain water intake.
2. Liver disease and bilirubin
Conjugated bilirubin is a water-soluble form of bilirubin produced by the liver. In liver disease (hepatitis, cirrhosis, biliary obstruction from gallstones or tumour), conjugated bilirubin accumulates in the blood and is excreted through the kidneys rather than through bile. This produces the classic tea-coloured or brown urine of jaundice. The triad: dark brown urine + pale/clay-coloured stools + yellow eyes and skin. Seek same-day or next-day care. See the full liver signs guide.
3. Rhabdomyolysis (myoglobinuria)
Rhabdomyolysis is the breakdown of damaged muscle tissue, releasing myoglobin (a muscle protein) into the bloodstream. Myoglobin is cleared by the kidneys but is directly toxic to renal tubules in high concentrations - it can cause acute kidney injury. Causes include extreme physical exertion (ultra-marathons, military training), crush injuries, seizures, heat stroke, severe alcohol intoxication, and some medications (statins at high doses, rarely). The urine colour is typically brown or tea-coloured - classically described as "cola-coloured" - and occurs alongside severe, widespread muscle pain and weakness. This is a medical emergency requiring intravenous fluids in a hospital setting.
4. Medications
Several medications cause brown or dark urine as a known side effect: metronidazole (Flagyl) - common antibiotic; nitrofurantoin - UTI antibiotic; methyldopa - antihypertensive; levodopa - for Parkinson's disease; chloroquine and hydroxychloroquine - antimalarials; cascara and senna laxatives. If you started a new medication recently and have no other symptoms, consult your pharmacist - the medication is likely the explanation.
5. Porphyria
Porphyrias are a group of rare genetic conditions affecting haem production. They can produce brown or dark red urine (sometimes described as port-wine coloured) during attacks. Attacks are often triggered by certain medications, fasting, or alcohol. Diagnosis typically requires specialist input.
6. Foods
Fava beans can cause dark brown or black urine in people with G6PD deficiency - a genetic condition requiring urgent assessment when urine darkening occurs. Rhubarb in large quantities can also produce dark urine.
When to Seek Care
Emergency (call 911/999): Brown urine plus severe muscle pain after extreme exertion, seizure, or crush injury (rhabdomyolysis); brown plus confusion or extreme weakness.
Same-day GP: Brown plus yellow eyes or skin; brown plus right-side abdominal pain; brown plus pale stools; brown with no obvious cause.
Book within a few days: Brown that cleared after starting a new medication and you have no other symptoms - confirm with pharmacist.
Monitor: Brown from known medication side effect (metronidazole, nitrofurantoin) - no other symptoms, discuss with GP at next opportunity.
Frequently Asked Questions
What causes tea-coloured urine?
Tea-coloured or cola-coloured urine is typically caused by either liver disease with bilirubin overflow, or rhabdomyolysis (muscle breakdown releasing myoglobin). Both require medical assessment. Severe dehydration can also cause dark brown urine but typically corrects with rehydration.
Can drinking water fix brown urine?
If the cause is severe dehydration, aggressive rehydration will help and urine will lighten. If the cause is liver disease, rhabdomyolysis, or a medication, drinking water alone will not fix the brown colour - the underlying cause needs assessment.
What is rhabdomyolysis and how do I know if I have it?
Rhabdomyolysis is breakdown of muscle cells, releasing myoglobin into the bloodstream. Signs: brown or cola-coloured urine, alongside severe widespread muscle pain and weakness, usually after extreme exercise, seizures, or crush injury. It can cause acute kidney injury and is treated with IV fluids in hospital. If you have these signs, seek emergency care.
Is brown urine always serious?
No - if you are taking metronidazole, nitrofurantoin, or certain other medications, brown urine is a documented side effect and not dangerous. But brown urine without a clear medication explanation, especially with other symptoms, warrants same-day assessment.
Sources: Mayo Clinic; Cleveland Clinic; NHS rhabdomyolysis page.