If it is the same kind, but a different brand that is ok. Now if you're switch types of formula, it can cause bad gas and sometime spit up.

Don't just switch the formula 1st mix some of the old with the new And see how baby react to that. Enfamil gentlease is a good formula for gassy babies I use it on my baby

Which one u switch too @twinmommy523

I use the similac also and had a bad experience with changing it on my girls. They got really fussy and uncomfortable then when we went back to it they were fine after a few days.