My kitten just threw up?

Well... My brother's cat does that all the time. It seems like he's bulimic! >D But anyway. I'm not sure. Are you feeding her kitten food? Kittens can only have KITTEN food. My 11 week kitten walks around and eats my older cat's food. Then she throws it up. So I would only feed her kitten food. Otherwise, you would have to talk to the vet. I hope I helped, and I hope your kitten will be okay!