My baby has lots of phlegm backed up in his throat. What can we do?

Lots. This question has different offerings depending on age. Infants may need a formula change as dairy products actually can thicken phlegm (even though some studies say to the contrary). Breastfeeding moms eating dairy=same affect. Older kids may have allergies and some meds may help reduce phlegm. I do have success with chinese herbs in all ages. Find a chinese medicine practitioner in your area.