melanuria

[mĕl′ə-nurē-ə]
n.
  1. The excretion of urine of a dark color, resulting from the presence of melanin or other pigments or from the action of coal tar derivatives.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.