Normally, dilute urine is nearly colorless. Concentrated urine is deep yellow. Colors other than yellow are abnormal.
Drugs can produce a variety of colors: brown, black, blue, green, orange, or red.
Brown urine may be caused by broken-down hemoglobin (the protein that carries oxygen in red blood cells). Broken-down hemoglobin can leak into the urine when bleeding occurs in the kidney, ureter, or bladder, or it can be excreted into the urine as the result of certain disorders that damage or destroy red blood cells (hemolytic anemia). Brown urine also may be caused by muscle protein (myoglobin) that is excreted into the urine after severe muscle injury.
Urine may be black because of pigments produced by melanoma.
Red urine may be caused by blood (see Symptoms of Kidney and Urinary Tract Disorders: Urine, Blood in) but it may also be due to food pigments (eg, beets), artificial food coloring, and rarely by porphyria (see Porphyrias).
Cloudy urine suggests the presence of excess white blood cells due to a urinary tract infection, the presence of crystals of salts from uric acid or from phosphoric acid, or the presence of a vaginal discharge.
Doctors usually can identify the cause of an abnormal color by examining the urine under a microscope or by doing chemical tests. Treatment is unnecessary except if needed to treat the underlying disorder.
Last full review/revision March 2013 by Anuja P. Shah, MD