I hope this is helpful although it's as contradictory asall advice seems to be - Green poo Says Vicky Pigott: 'If your baby's stools are green and frothy she may be taking in too much lactose (the natural sugar found in milk), which happens if she feeds often, but doesn't get the rich milk at the end of the feed to fill her up. It may also be caused by overfeeding or underfeeding, or is a sign that your baby has a stomach bug.'
Green stools in a baby who is receiving nothing but breastmilk are a warning sign that all is not well. If your baby's stools are nearly always green and if he is not gaining weight well even though your milk supply seems fine, then it could be that he is getting too much foremilk and not enough hindmilk. As the foremilk is more dilute, with more lactose and less calories, it stimulates your baby's digestive tract to move the milk along too fast producing green, often explosive, nappies!
If you are taking him off the first breast before he comes off spontaneously, try waiting until your baby finishes the first breast to get enough hindmilk before offering the second breast; it may even be that he will only need one breast per feed. Ask a breastfeeding counsellor or infant feeding specialist to check that your baby is properly latched on and that he is managing to extract all the calorie-rich hindmilk.
Consistently green stools could also be a warning that your baby is sensitive to something. Is he on any medication? If not, could he be sensitive to any medicines that you are taking, like iron supplements or antibiotics? Very occasionally, a baby can become sensitive to something in his mother's diet which is passed to him through her breastmilk. In this case other symptoms, such as eczema or a rash, may be present. It can be hard to pinpoint the trigger. If you suspect your baby has a food allergy or intolerance, you should talk it through with a dietitian or breastfeeding counsellor. Your baby may also have diarrhoea if he has a viral or bacterial infection, in which case, make an appointment to see your GP.