What causes black urine?

November 3, 2010, 11:49 pm


A case of black urine and dark skin – cresol poisoning. Seak CK et al. Clin Toxicol 2010 Oct 6 [Epub ahead of print]


Cresol — derived from phenol — is a common disinfectant.  Acute cresol toxicity presents with corrosive gastrointestinal injury and multi-organ failure. Another characteristic finding in cresol poisoning is black urine.  This case report — describing a 42-year-old man who ingested cresol in a suicide attempt — is illustrated with a photograph of the strikingly dark urine.

As the authors note, other causes of black urine include hemoglobinuria, myoglobinuria, alcaptonuria, melanuria, porphyrinuria, tyrosinuria, and malignant melanoma.

Addendum (11/10/10): Chris Nickson from Life in the Fast Lane wrote to point out that last year Annals of Emergency Medicine published a very similar case of cresol poisoning, with a great picture of the urine.  To read the brief report and see the picture, click here.


  1. precordialthump Says:

    Hi Leon,
    There is also a nice clinical image in EM from AnnEmergMEd that is free fulltext online with a great photo of black urine.

    ‘A Man With Black Urine’: http://www.annemergmed.com/article/PIIS0196064408019768/fulltext


  2. Leon Says:


    Thanks. I saw that image when searching through our university library system yesterday, but didn’t realize it was available for open access. I’ll add a note to my post linking to the page.

  3. Neuroskeptic Says:

    Jesus. I’m struggling to think of a less pleasant suicide method.