What can you do for congestion for babies 4 months and under?
A humidifier may help a lot. Saline nose drops or sprays may help as well.
Don't give your baby any medicines not prescribed by your pediatrician. My Dr. used to prescribe albuterol for my daughter when she was a baby and had a cold or flu.
I've had a look and come up with two popular things called nose drops and bulb suction. Also sleeping upright eg. in a car seat. Go to the local pharamcist and ask them what they would recomend.