Vomiting in Cats

Question
I have a 9-month female spayed tabby.  The last few days she hasn't seemed particularly interested in her normal wet food (although she does eat some of it), and she does eat her dry food.  This morning I happened to be with her when she vomited up what appears to be a bunch of undigested dry food.  This is the first time, as far as I know, that this has happened.  There was no hair in the vomit.  (She does bring up a hair ball on occasion.) She has been using the litter box as she normally does.  What would cause this vomiting?  Thanks.  

Answer
im not sure what might be causing it, but try giving her some cat laxative (you can buy it at the vet, dont get the one at walmart or the grocery store) about every 2 days and if she still isnt back to playing and being a normal young cat, take her to the vet. most likely she just has a boo boo belly.....it happens