Green stools and gassiness in baby

My son's stools have turned green and he is gassy. While we were waiting for results of a stool sample I supplemented with soy formula and his stools returned to a mustard yellow color. The results of the test was negative and I resumed full breastfeeding two days ago. His stool has turned green again. Is there something I may be doing to cause the green stool?


Debbi Donovan

Debbi Donovan is a Board Certified Lactation Consultant, as well as a retired La Leche League Leader. For more than a decade, Debbi... Read more

Green stools and gassiness in an otherwise healthy breastfed baby are often caused by a foremilk/hindmilk imbalance. This sounds very complicated, but it really isn't. Foremilk is the thinner, lower fat milk your baby receives at the beginning of a feed. It transitions to the hindmilk which is higher in fat.

This problem often occurs when the mom has a very abundant milk supply. It can also occur when the baby is switched from one breast to the other after a set period of time, and when the baby doesn't achieve a good latch-on. The baby is getting an abundance of foremilk and not much hindmilk. This can cause fussiness(colic), gassiness, green frothy stools, unhappiness at breast and breast refusal. A baby who is getting too much foremilk may want to feed frequently or for very long periods of time. He is often getting a high volume, lowcalorie feed.

Your baby's green stooling and fussiness can result from too much lactose(sugar). High volume feeds are invariably, high lactose feeds. When the excess lactose enters your baby's colon there may be increased fermentation, resulting in colic, gas and loose, acid stools.

Low-fat feeds (of mostly foremilk) are very rapidly digested. An infant will be hungry again soon after feeding. This will further stimulate the mom's milk production, often resulting in oversupply and further complicating the situation.

To help remedy this situation, allow your baby to control the feed. When nursing, let your little one come off the first breast on his own, relaxed and satisfied. If your baby is properly positioned and attached, taking in a good mouthful of breast, allow him to feed as long as he wants. You can offer the other breast, though many babies are quite content nursing from one side per three to four hour period. During the first three or four days, as your milk supply is adjusting, express just enough milk from the "unused" or "less used" breast for comfort.

If this problem persists, I would recommend working with a Lactation Consultant. To locate an IBCLC (International Board Certified Lactation Consultant) you can contact the ILCA (International Lactation Consultant Association) office. You will be referred to three IBCLC's in your area. You can reach them at:

200 N. Michigan Ave, Suite 300
Chicago IL 60601
phone 312-541-1710
fax 312-541-1271.

Wishing you the best!

Watch Video: When is breastfeeding okay?

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