Jenannen
Well, I'm not this doctor so I'm not entirely sure, but my guess would be that he's talking about the fussing if she does not get what she would like to eat.
Babies typically take comfort in suckling/sucking. Even now that El's almost 2 she still likes to suck her thumb to go to sleep, though that's about the only time she does still stuck her thumb.
My best guess is that he was saying that her fussiness about that was colic. I can't see how it would be though.
If this is not your typical doctor though I would certainly bring it up with her!
Also for diarrhea depending on how old she is you may want to keep in mind the BRAT diet.
Bananas
Rice
Applesauce
Toast
Of course if she's still too young for solids you don't want to start her on them! O: I will have to learn more about this brat diet seeing as how in a few months she will be old enough for rice cereal and baby food.
And Im glad im not the only one who thought it was weird for him to say colic about being fussy.
And kaylee only lately has wanted to suck on things to go to sleep half the time she doesnt want it.