Green poos at three months could mean:
- Your baby is getting too much foremilk, and not enough hindmilk. If this is the case, he may be suffering from colic, too. You can resolve this by adjusting your breastfeeding technique (see below).
- Your baby is sensitive to medication. Is he taking anything? Or could he be reacting to medicines that you’re taking, such as antibiotics or iron supplements?
- Your baby is sensitive to something you’ve eaten. He may have other symptoms, such as eczema or a rash. See your GP if your baby has these symptoms.
- Your baby has an infection, especially if he also has diarrhoea. Take him to see your GP or practice nurse.
http://www.babycentre.co.uk/x543050/why-are-my-breastfed-babys-poos-often-green#ixzz2Jl6AWEhD