Hi - my DS also has green poos alot (I sometimes feel we've become poo obsessed) - but often of the explosive diarrhoea type. Anyway, the child health nurse (and MIL) reckon he's a bit of a glutton, and that's why. The peadiatrician suggested expressing some foremilk before starting for a few days to give the bowel a break from higher-sugar milk. That seemed to clear it up right away, though he's still doing green poos at times.