Green Stools

Dear Lisa,

My 6 week old nephew has been given Mylicon for gas/colic. He is a formula baby and we have given him prune/apple juice for constipation. His poop color is dark green, almost black and a little watery. Why is his poop this color?

“Concerned Aunt”

Dear “Concerned Aunt”,

The stools of bottle-fed infants can vary in color. The colors change according to what the baby eats or due to the medications that he takes. Normal colors include shades of green, brown or yellow depending upon the formula. (1) Some shades of green may appear almost black in color. On the other hand, babies that are exclusively breast fed and not taking iron vitamins are not expected to have green stools. Green stools in this case may be a sign that the baby is not receiving enough milk.(1) Any infant with very light colored stools, grey stools, black stools or stools with visible blood should be evaluated by a Health Care Professional.

Therefore your nephew’s stools sound like they are normal. If you are not sure if the color is black it would be a good idea to bring this the Doctor’s attention. His doctor may need to visually inspect the stool to see if the stools are truly black. Since black colored stools may be a sign that there is blood in the stool, the doctor may want to test the stool.

Blood in the stool turns black when it is not fresh blood. This occurs when the blood enters the system high in the gastrointestinal tract. (2) For example, this can occur if blood enters the stomach or the small intestine. The stool turns black during the transition to the large intestine.

Testing stool for blood can be done with a very simple test called the Hemoccult or Guaiac test. (2) In order to test stool for blood the specimen should be obtained from fresh stool collected on three consecutive days (three days in a row). This is simple when a child is still in diapers. Simply remove the diaper when the infant has a fresh stool and label it with the date. It is important to collect a fresh specimen because the test will not be accurate if the stool is mixed with urine or water. (2)

For older children who no longer wear diapers, the stool can be collected by putting plastic wrap (i.e. Saran Wrap) over the rim of the potty or toilet bowl. The child can have a bowel movement and the plastic wrap will catch the stool and prevent it from mixing with the water in the toilet.
Once the stool specimen is obtained, small specimens collected from two different spots of the stool are smeared onto a guaiac card. A couple of drops of a reagent solution are put on the specimen card and if the window turns blue it means there is blood in the stool. (2)

References:
(1)Chow M, Durand B, Feldman M, Mills M. Handbook of Pediatric Primary Care. Albany, New York:Delmar Publishers Inc. 1984: 291.
(2)Kozier B, Erb G. Fundamentals of Nursing. Concepts and Procedures. 2nd Ed. Menlo Park, California: Addison-Wesley Publishing Company.1983:688-700.

Lisa-ann Kelly R.N., P.N.P.,C.
Certified Pediatric Nurse Practitioner

Pediatric Advice About Keeping Infants Healthy