Re: Yellow stool

Green

Food is moving through the large intestine too quickly, such as due to diarrhea. As a result, bile doesn't have time to break
down completely. Green leafy vegetables, green food coloring , such as in Kool-Aid or popsicles, iron supplements.

Light-colored, white or clay-colored

A lack of bile in stool. This may indicate a bile duct obstruction. Certain medications, such as large doses of bismuth
subsalicylate (Kaopectate, Pepto-Bismol) and other anti-diarrheal drugs.

Black

Bleeding in the stomach or esophagus. Iron supplements, bismuth subsalicylate (Kaopectate, Pepto-Bismol), black licorice.

Bright red

Bleeding in the rectum. Beets, red Jell-O or Kool-Aid.

Stool starts out green , then turns bright yellow as it goes through the digestive tract. It is bile and bacteria that finally turn it brown. Yellow or green stools can indicate stool is passing through the digestive tract too rapidly not giving it a chance to change colour. Bright yellow stools can also indicate not enough bile / bilary obstruction.