What can I add to baby's milk. Not cereal! ?

Just milk! There is no need to add anything to the milk. Cereal is recommended between 4-6 months of age but not to added to the milk.
I generally don't. Babies milk, whetherbreast milk or formula is a simple nutrition source that requires no additives. If you need it thickened for some reason, formula powder can do the trick. If baby is ready to move into solids, the focus in on a new feeding method, not what they eat.Cereals cause few food reactions & easy to store. Mashed up vegies, fruits etc. Offered from a spoon is the preferred method.