i think my cat ate a poisonous plant

Question
Hello, I have a 1 year old cat (long hair domestic) we got from the shelter at
11 weeks old and another cat about 1 yr 8 months  (short hair domestic) we
also got from a shelter at 8 months who are both fixed and full time indoor
cats, never been outside.  Well long story short they are best buds and we
normally have cat grass available but we havent for about a month or more
and recently we noticed the little guy(Blue) started eating our houseplant
which we got a long time ago(lost the tag so i dont know what kind it is.  He
was fine for a while after doing so but then recently started getting sick and
throwing up.  He is a crazy eater always begs for food, eats really fast and
anything he can find but he's real skinny and really hyper so we see no
problem with it although he never gets people food and eats purina natural
dry food.  So anyway he started throwing up frequently throughout the day
but continued playing and eating and drinking water which still is the case.  
But I have noticed he only throws up when myself and my girlfriend are
around and find the chewed plant leaves in his puke (no longer since we put
the plant out of reach) but he still throws up sometimes stomach acid
sometimes food unchewed sometimes fully chewed.  His activity level is
normal still crazy plays all the time and loving up in our face and lap.  He is
eating normally and drinking and going the bathroom fine no blood found in
anything like feces or puke.  Should I be concerned, it's been 3 days now with
the plant not around and his puking has slowed down only when we are home
a couple of times a day when he used to do it only once a day after eating to
fast.  What should I do?    Thank You..........ps he is up to date on shots and
vet visits regularly they see nothing wrong but I think he was poisoned?

Answer
Plants very commonly do cause vomiting in cats.  In fact it is often believed that feral cats eat grass outdoors for the emetic effect. If the vomiting has resolved for the most part I would attribute it to the plant that your removed, with the occasional regurgitation caused by eating too quickly.

If he continues to vomit, especially just fluid there is the possibility of acid reflux, however this is more common in older cats.  If he has continued the vomiting I would recommend taking him to your veterinarian to pursue this or other causes.

Apologies for this delayed response.  I was unexpectedly unavailable due to a family emergency.