Black or Brown Urine

Brown UrineIf you have urine that is black or brown, it is understandably distressing. Fortunately, the most likely cause of black urine/brown urine is that you ate certain foods or it’s a side effect of a medication you took. In some cases, though, it can be a sign of disease.

The first part of this article is about black and/or brown urine, while the second part is about black urine in particular.

The foods you eat could be the cause of your black/brown urine. The top three foods that can cause this are aloe, rhubarb and fava beans (also called broad beans or field beans). If you have black or brown urine from eating these foods, it is harmless and will go away in a day or two.

Medications that Cause Black or Brown Urine

Some medications have black/brown urine as a side effect. If you have recently taken a new medication, check with your doctor or pharmacist whether black/brown urine is a side effect.

These medications are known to sometimes cause black/brown urine as a side effect:

Metronidazole (Flagyl)- an antibiotic, especially used for Clostridium dificile infections.  It is also used in anti-rosacea creams or gels, although the cream or gel versions are unlikely to turn your urine black or brown.

Furazolidone- an antibiotic/anti-microbial medication

Methyldopa (Aldomet)- a treatment for high blood pressure, especially pre-eclampsia in pregnant women. Methyldopa’s metabolites turn black when they come into contact with bleach, which is present in many toilets.

Chloraquine- a drug used to prevent malariaPrimaquine- a medication used to treat malaria and sometimes pneumoniaNitrofurantoin- an anti-biotic often used as a treatment for urinary tract infections (UTIs)

Cascara or Senna- ingredients in some laxatives

Methocarbamol- a muscle relaxer used to treat muscle spasms

Sorbitol- has many uses, including as a laxative and as a sugar substitute.

Contamination with Betadine (povidone-iodine) solution can turn urine brown (this could possibly happen while douching).

Diseases that Cause Brown or Black Urine

Some health conditions and diseases can cause black or brown urine. Alkaptonuria, a rare genetic disease, is one example. People who have alkaptonuria may have urine that gets darker and darker the longer it is exposed to air/left standing.

Melanoma can also cause urine that gets darker and darker as it is left exposed to air. This is due to the melanin and melanogen in the urine. This kind of black/brown urine will darken from the top down, which can be seen if the urine is in a clear container.

Tyrosinosis, a metabolic disorder, can cause a person’s urine to appear brown or black.

Porphyria cutanea tarda, a disease that affects heme in the body, may case brown/black urine as a symptom. However, the main symptoms are blistering or the detachment of nails from the nail bed after exposure to sunlight. People with this type of porphyria also often have liver problems.

Black Urine

Laxatives and Black Urine

Laxatives that use senna or cascara may cause black urine. Senna is a plant product and is often found in “vegetable laxatives” or “all-natural” products. These brands have at least one product that contains senna:

  • Senokot
  • Walgreens Senna Tablets
  • Smooth Move
  • Goldline
  • Sunmark
  • Fieldtex
  • Traditional Medicinals
  • Mason Remedies
  • McKesson

Cascara is another laxative ingredient that might turn your urine black. It is from a buckthorn species of plant. These brands have at least one product containing cascara:

  • Puritan’s Pride
  • Nature’s Way
  • NOW Foods
  • Heughan’s

Senna and cascara are not known to be harmful. Black urine caused by these substances should resolve within 1-2 days.

Malignant Melanoma

Melanoma, an aggressive type of cancer, can cause black urine due to the melanin in it.

Black Urine Disease (Alkaptonuria)

Another possible cause is a rare genetic condition called alkaptonuria (AKA black urine disease). Alkaptonuria is a genetic disorder that causes the body to have trouble metabolizing tyrosine and phenylalanine. Black urine disease is particularly common in the Dominican Republic and Slovakia, compared to other countries in the world.


Hemoglobinuria- excess hemoglobin in the urine- may cause black urine, but it could also result in red or brown urine instead. Hemoglobinuria is when you have high levels of hemoglobin, a component of your blood, in your urine. There are many possible causes for hemoglobinuria, including:

  • Burns
  • Acute glomerulonephritis (a kidney disease)
  • Kidney cancer
  • Malaria and medications used to treat malaria
  • Exposure to arsenic gas

If you have black urine, you should seek medical advice as soon as possible, especially if you have any other symptoms.




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