Whats Wrong With My Cat?!?Hes Balding?!?!

:confused: I am worried about my 6 year old orange tabby cat Joker. My dad says its nothing to worry about so he doesnt want to take him to the vet. But for the past little while my cat has been licking his belly more then usual. For a while now maybe a year it has slowly turned into a bald spot on his stomach. He hasnt changed in his personality or anything. He has also been throwing up alot ever since his belly is bald. I know he licks himself and now his legs are slowly going bald (it is sort of funny to see) but I hate that he keeps throwing up. My dad thinks its only because he keeps eating one of our plants (dont worry not poisionous). I was wondering if anyone knows a solution or anything. My dad has bought a hair ball stopper but hasnt used it yet I think it might be a gel...
Thanks for anyone who can read and post a reply:confused:

Cats usually overgroom themselves this way due to stress or parasites like fleas.

Has anything in the home changed since he started doing this? Does he live indoors? Are there any stray cats hanging around your house who might be spraying?

IMO, a cat vomiting and losing fur is something to worry about, so your dad should take him to the vet. How much has to happen before your dad worries?:confused: