breast milk or formula?? I only ask because breastfed babies could take up to a week to poop sometimes. any way my pediatrician had told me to try some sugar water. 1tsp of sugar to 1-2 oz of water.
You can use gas drops or the medicine gripe water or you can take a q tip with Vaseline on the tip and only stick the q tip in but be prepared because it can work almost instantly
gas drops can acutally make them more constipated. my son's peds reccomeneded pedialyte either inbetween feeds or a little before or after. they also switched his formula to Enfamil reguline. it's supposed to regulate their bowels and so far it's worked wonders for my son