Although it is somewhat normal for looser stools during teething due to swallowing lots more saliva etc, and to not want to take a bottle as often, because it hurts to suck at times, it sounds like your little guy may have found himself a little stomach bug. I would try to lay off of the formula a abit, and give him pedialyte instead for a bit. We personally like the Gerber liqui-lyte (I think that is what its called), and they even come in small bottles, so you dont waste as much. Just let his belly settle alittle, and then start adding formula back in. That is just my advice, good luck! ~A.~