Bright green stool is not a cause for worry, according to Mayo Clinic. Normal stool colors include shades of brown and green. The bright green color could be an indicator that the stool is moving through the digestive track rapidly or of food the person consumed, such as leafy greens.
Stool color is rarely a cause for concern, according to Mayo Clinic. Most of the color comes from the breakdown of bile, an enzyme produced by the liver that helps to break down fats. As the bile passes through the intestines, chemical changes result in a wide range of colors. If the individual is experiencing diarrhea, there is little time for bile to break down, and it remains green.
Food manufacturers sometimes add coloring agents to make their products more appealing. These natural and artificial colors have the potential to affect stool color, reports Mayo Clinic. Green drink mixes, artificially colored dry cereals and freezer pops all have the potential to affect stool color.
Some stool colors create a larger health concern than others. For example, Mayo Clinic indicates stool that is light-colored white or clay-colored could indicate a bile-duct obstruction. Bright red or black stool sometimes indicates bleeding in the digestive tract.