#2 Lactose overload
With oversupply, a baby may be getting an excess of high lactose (sugar), lower-fat milk making it difficult to digest the lactose properly causing the foamy, watery, green poop.
Lactose intolerance: Greenish stools along with flatulence may be indicative of lactose intolerance (congenital or acquired). Stopping milk and milk products may help with this issue.
Lactose intolerance symptoms include wind, stomach pain, bloating, rumbling tummy and diarrhoea. Babies with lactose intolerance might also have nappy rash. Most breastfed babies with lactose intolerance can still breastfeed. See a GP about formula-fed babies.
Loose stools
Sometimes your child might pass loose, watery, yellow and green coloured stools after two hours of consuming milk or any other dairy product. This could be a sign of lactose intolerance in the baby.
It can be tricky to distinguish between the two but they're actually completely different conditions. A food allergy, such as cow's milk allergy, is an immune reaction to the protein in milk. A lactose intolerance is caused by the inability to break down lactose, which is the sugar in milk.
Green poop may indicate a foremilk/hindmilk imbalance in breastfed babies, which results in your baby is getting a larger portion of foremilk (watery milk) than hindmilk (thicker, fattier milk). Though this can cause tummy discomfort, it doesn't indicate a milk supply issue or problem with your milk.
Green Baby Poop: Babies taking an iron-supplement will often have green baby poop. Green baby poop can also occur at 4 to 6 months when they start eating solid, green foods, such as pureed peas, spinach and beans. Orange, Yellow and Brown Stools: These colors are normal in breastfed and bottle fed babies.
If frequent green poop is coming from a baby who is also fussy or develops other allergy symptoms, like a rash or runny nose, the cause may be an allergy or sensitivity to a food in the mother's diet. Talk with a La Leche League Leader or lactation consultant for ideas to help with overabundant milk or food allergies.
Food Intolerance
According to Dr. Palmer, a cause of green baby poop could be food intolerance—either to something in breast milk or the baby's formula— though this isn't typical. Most babies will present with blood in their stool or red poop from food intolerances.
Tan is too! When a baby is on hypoallergenic formula, the first stools tend to be green and can be dark. In fact, lots of you describe the color as hunter green (but contact your baby's doctor if stools look black, which may be blood in the stool).
Formula-fed babies may have green poop if the formula they drink has an iron sulfate supplement or is iron-fortified. Sometimes stool can even be so dark green that it looks black. This is no cause for alarm and has no significant effect on your baby's digestive system.
Lactose overload is often seen in young babies when their mums make too much milk. They take large amounts of breastmilk and may be 'windy', crying or hard to settle after feeds. Your baby may have more wet nappies and poos than normal in 24 hours. The poos may be green and frothy or explosive.
Breastfed baby poop is considered normal when it's a mustard yellow, green or brown color. It is typically seedy and pasty in texture and may be runny enough to resemble diarrhea. Healthy breastfed stools will smell sweet (unlike regular bowel-movement odor).
Call your doctor if you or your child has green stool for more than a few days. Green stool often occurs with diarrhea, so drink plenty of fluids and seek immediate medical attention if you or your child becomes dehydrated.
Greenish stool could indicate that you have a bacterial infection (salmonella or E. coli, for example), viral infection (norovirus) or a parasite (Giardia) causing a rapid transit “gush” of unabsorbed bile.
In some cases, a hydrogen breath test is done to test for lactose intolerance. For the test, your child breathes into a container that measures breath hydrogen level before and after he or she drinks a beverage that contains a known amount of lactose.
Potential Side Effects of Lactose-Free Baby Formula
Symptoms include bloated bellies, loose stools and colic. Symptoms of bacterial infection from contaminated formula include crying, fatigue, fever and poor feeding.
Symptoms of Dairy Allergy in Breastfed Babies
The proteins in cow's milk can cause gas in a baby's stomach and intestines, which can lead to pain, vomiting, or diarrhea. A food allergy could also cause reflux, symptoms of colic, a rash or hives, swelling, a runny nose, wheezing, and bloody poop.
Light green: Consistent green stools in a breastfed baby can indicate an imbalance of foremilk/hindmilk. Foremilk is the low-calorie milk that comes first in a feeding. Hindmilk, which is high in fat, comes second in a feeding. Try feeding longer on each breast.
Vomiting. Blood or mucus in your baby's stool. The baby often pulls her legs up toward her belly because of pain. Difficulty with weight gain or noticeable weight loss.