Brown urine is usually a sign of dehydration, but it can also point to medications you’re taking, certain foods, or less commonly, a problem with your liver, kidneys, or muscles. The single most common reason is simply not drinking enough water. If you drink a large glass or two and your urine lightens within a few hours, dehydration was likely the cause. If it stays brown despite good hydration, something else is going on.
Dehydration Is the Most Common Cause
Your urine gets its yellow color from a pigment called urochrome, which your body produces as it breaks down old red blood cells. When you’re well hydrated, that pigment is diluted and your urine looks pale yellow or straw-colored. When you haven’t had enough fluids, the same amount of pigment is concentrated in much less water, pushing the color from dark amber toward brown.
You’ll usually notice other signs alongside the color change: stronger-smelling urine, smaller volumes when you go, dry mouth, or fatigue. Rehydrating steadily over a few hours is typically enough to bring urine back to a normal pale yellow. If you’ve been sweating heavily, exercising in heat, or simply forgetting to drink, this is almost certainly your answer. Aim to sip water consistently rather than chugging a large amount at once, which your kidneys will just flush out quickly.
Medications That Turn Urine Brown
Several common medications can darken urine to a brown or brownish-orange shade, even when you’re perfectly hydrated. The Mayo Clinic lists these among the known culprits:
- Certain antibiotics, particularly metronidazole and nitrofurantoin
- Senna-based laxatives (found in many over-the-counter constipation products)
- Antimalarial drugs like chloroquine and primaquine
- Muscle relaxants such as methocarbamol
- Cholesterol-lowering statins
- The seizure medication phenytoin
This type of color change is harmless. It starts when you begin the medication and resolves after you stop taking it. If you recently started a new prescription or supplement and noticed your urine turning brown around the same time, that connection is worth checking with your pharmacist.
Liver and Bile Duct Problems
Your liver constantly breaks down old red blood cells into a yellow waste product called bilirubin. Normally, your liver packages bilirubin into bile, which flows through small tubes (bile ducts) into your intestines, where it helps digest food and eventually leaves your body in stool. A healthy liver removes most bilirubin this way, so very little ends up in your urine.
When the liver is inflamed or damaged, or when bile ducts become blocked (by gallstones, for example), bilirubin backs up into your bloodstream. Your kidneys then filter it out, and it shows up in your urine, turning it a dark tea-brown color. This is one of the classic early signs of liver disease or gallbladder problems. You’ll often see a second clue at the same time: unusually pale or clay-colored stool, because the bile pigment that normally darkens stool is being diverted into your urine instead. Yellowing of the skin or eyes (jaundice) may appear too.
If your brown urine comes with pale stool, abdominal pain (especially in the upper right side), nausea, or a yellowish tint to your skin, these symptoms together suggest a liver or bile duct issue that needs medical evaluation.
Muscle Breakdown (Rhabdomyolysis)
When muscle tissue is severely damaged, muscle cells release a protein called myoglobin into the bloodstream. Your kidneys filter it out, and it turns urine a distinctive dark brown, often described as tea- or cola-colored. This condition, called rhabdomyolysis, can happen after extreme exercise (especially if you’re not conditioned for it), crush injuries, prolonged immobility, heatstroke, or certain drug reactions.
The brown urine from muscle breakdown looks similar to the brown urine from liver problems, but the accompanying symptoms are different. With rhabdomyolysis, you’ll typically have significant muscle pain, weakness, and swelling in the affected area. The combination of dark brown urine and severe muscle soreness after intense physical activity is a red flag. Myoglobin can damage the kidneys if not treated promptly, so this scenario warrants urgent care.
Kidney Problems
Certain kidney conditions cause red blood cells to leak into your urine. When enough blood mixes with urine, the result isn’t always obviously red. It can look brown or cola-colored instead, especially when the bleeding comes from the tiny filtering units deep inside the kidney. Glomerulonephritis, an inflammation of those filters, is one well-known cause of cola-colored urine. It can develop after infections, autoimmune conditions, or other triggers that damage the kidney’s filtration system.
Brown urine from kidney bleeding may come alongside puffiness in the face or ankles, reduced urine output, or elevated blood pressure. Sometimes it appears with no other obvious symptoms at all, which is why persistent brown urine that doesn’t clear with hydration deserves investigation.
How Doctors Tell the Difference
A standard urine test can quickly narrow down the cause. The dipstick portion of the test reacts to blood, but it also reacts to myoglobin (from muscle breakdown) and free hemoglobin (from red blood cell destruction). So a positive result on its own doesn’t distinguish between those three possibilities. To sort them out, the lab examines the urine under a microscope. If intact red blood cells are visible, the source is bleeding somewhere in the urinary tract or kidneys. If the dipstick is positive but no red blood cells are seen, that points toward myoglobin or hemoglobin instead. The test can also detect bilirubin, which flags liver or bile duct problems.
What to Do First
Start by drinking water. If dehydration is the cause, you should see your urine lighten noticeably within a few hours. Think about whether you’ve recently started any new medication, supplement, or herbal product, since that’s the second most common explanation.
If your urine stays brown after a full day of solid hydration, or if it comes alongside any of these symptoms, it’s time to get it checked: severe muscle pain or weakness, abdominal pain, pale stools, yellowing skin or eyes, fever, or pain during urination. Brown urine that appears after intense exercise along with muscle soreness should be evaluated promptly rather than waited out, because kidney damage from muscle breakdown progresses quickly when untreated.