Green poo!

[swmum]

I know - a lovely subject! Just wondered if anyone could shed some light on this please.
Am mix feeding - about 50/50 - and suddenly in the last few days my son (13 weeks) has been having green pasty poos. Not the nice yellow ones I know he is supposed to be having.
Has anyone encountered this?
Is it something to be concerned about?
He feeds on each boob for about 10 mins and takes about 150mls of formula when I feed him that. Poos once a day and lots of widdles.
Not freaking out about it but would like to know why the poos have changed?

I think it's formula - DD did quite glowing green ones on C&G premium stuff having done the yellow ones when on breast milk. Can't give any further biological explanation but I don't think it's anything alarming. Wait until he's weaning !

You don't say how long have you been giving the formula? Or have you changed anything recently?

I think green poo is quite common but still quite alarming when your little one has it isn't it?

Just found this on babycentre:
'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.'