Cat keeps throwing up

Question
Our cat is 9yrs old, we've had him from birth.  (We don't know what breed) He stays insided, is extremely clean, and has no alergies we or his vet are able to detect and has been eating dry cat food.  Recently though he has been constantly throwing up, mostly right after he eats.  

Could you please offer some advice?

I have just switched him to canned food, hoping the change in food will help.  If not, what could it be?
Thank you, Ken  

Answer
HI Ken,

It is normal for a cat to throw up ever now and then,  from hairballs or just plain over eating.  But if this continues and you see weight loss, please take him to your vet.  It is possible there is an obstruction.  My sister had a kitten who swallowed a piece of thread that got caught on her lower teeth and was not visible.  The thread twisted around her intestines and cut them up.  It was a terrible thing, and although the kitten had surgery, she did not make it. I am not trying to scare you, but if it continues, please have him checked.  It may not be anything, and if it's not, then it will stop.   My cats often "pig out" then barf all over the house!!  (I hate when they do that!!)  Just use your common sense, and if he continues to eat and act hungry but doesn't hold it down, then please seek professional help.

God Bless,
Becky