Abnormal Stool in Children Underlying Cause
The most common causes of abnormal appearing stool in children include:
- Change in diet
- Medication side effect
- Food allergies
Dietary causes for red stool include:
- Large amounts of beets
- Tomato juice
- Tomato soup
- Red Kool-Aid
- Red gelatin
- Large amounts of red popsicles
Other causes for black stools include:
- Iron supplements
- Eating large amounts of foods rich in iron such as spinach and other greens
- Bismuth-containing compounds such as Pepto-Bismol
Normal Newborn Stool
Newborn stools appear different than those of children and adults. The first stool is normally thick, sticky and may be green-black or yellow in color. This occurs due to the buildup of material in the intestines during pregnancy. Breastfed infants usually have soft, seedy, mustard-colored stools. Eight or ten stools per day are common in a breast-fed infant. Formula-fed infants tend to have thicker, yellow to brown stools. Their stools are usually larger and have more odor than breast-fed babies.
Normal Infant Stool
Older infants will develop other stool changes after starting solid foods. Yellow, orange, green and brown stools are normal. Sometimes, red food dye can cause a red colored stool. By one year of age, stools should resemble those of an older child or adult.
- Crofts DJ, Michel VJ, Rigby AS, Tanner MS, Hall DM, Bonham JR. Assessment of stool colour in community management of prolonged jaundice in infancy. Acta Paediatr. 1999 Sep;88(9):969-74. 
- King TS, Elia M, Hunter JO. Abnormal colonic fermentation in irritable bowel syndrome. Lancet. 1998 Oct 10;352(9135):1187-9.