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Normally, dilute urine is nearly colorless. Concentrated urine is deep yellow. Colors other than yellow are abnormal.
Food pigments can make the urine red, and drugs can produce a variety of colors: brown, black, blue, green, orange, or red. Brown urine may contain 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 may contain muscle protein (myoglobin), which is excreted into the urine after severe muscle injury. Urine may be red because of pigments produced by porphyria, or black because of pigments produced by melanoma. Cloudy urine suggests the presence of excess white blood cells from a UTI, 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 performing chemical tests. Treatment is unnecessary except if needed to treat the underlying disorder.
Last full review/revision March 2007 by Ralph E. Cutler, MD
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