Why do feces vary in color so much less than the food they are results of? E.g. you may eat food of all kinds of different colors but the resulting feces will almost always be some shade of brown.

  • $\begingroup$ Answer the questions what is the cause of variations of colors in living organisms, such as plants and what happens to molecules during digestion, and you will have an answer. Maybe look at an Organic Chemistry and Biochem text book. $\endgroup$
    – AMR
    Aug 21, 2015 at 5:03
  • $\begingroup$ The reverse can also be true - products of newborns in their first weeks range from tar black, to green, yellow and brown, all on amniotic fluid and mother's milk :) $\endgroup$
    – AliceD
    Aug 21, 2015 at 13:01
  • 1
    $\begingroup$ The colors in feces can vary tremendously - the bilirubin answer posted below explains the brown tinge that's always present, but other colors can also be present, depending on the type of food and the presence of dyes or other chromagenic molecules. $\endgroup$
    – MattDMo
    Aug 21, 2015 at 16:42
  • $\begingroup$ feces color can vary with the food you eat. ever tried beets or eaten too much broccoli? $\endgroup$ Aug 22, 2015 at 19:39

1 Answer 1


The main reason for the color of our stool (or feces) is the presence of bilirubin, a breakdown product of the hemoglobin. The amount of it causes different variations from yellow to dark brown. When the passage time of the food in the intestine and the amount of bilirubin is constant, the color changes very little. Illnesses like diarrhea, which cause a lower passage time have therefore a ligher color because a lower amount of bilirubin can accumulate.

The color of the stool can also indicate illnesses of the internal organs, white stool (or pale clay like colored) can for example indicate problems with the biliary system (drainage system of the gallbladder, liver and pancreas).

You can find some more information here and here.


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