12 week old baby / green poo

[Kimdbs]

Hi there
My son is 12 weeks old. He is formula feed with cow and gate colic and constipation (this was great for our now toddler, when he was a baby) he has been on this since birth and has always had runny khaki poo
Should I be worried , is this normal?

I think that particular type of formula causes the green colour

Completely normal on the comfort formula, in fact I’m sure it actually states on the box may cause green poo.