From the time he was born, my son was a cranky baby.  I found that he was very gassy, even while breastfeeding.  When I heard about the Dr Brown bottles from my "Mommy and Me" class, I decided to give them a try.  What a difference!  I starting pumping and feeding with the Dr Brown bottles, and within two days, my son was less gassy and seemed to feel more comfortable overall.  His irritability went down several levels, and we BOTH began sleeping trhough the night!  :o)  I would recommend these to any parent dealing with a gassy, colicky or reflux prone infant.