Hello, and welcome.
My name is ***** ***** I will be glad to be of help to you and your kitty.
Vomiting in cats can have various causes. He may have hairballs that bother him, he may have food allergies. Cats can be allergic to any ingredient in their food, especially those that contain grain fillers like corn, and artificial ingredients like flavors, colors and/or preservatives. It's also possible that he may have ingested a non-food item or something toxic, or he could have a viral or bacterial infection in his digestive/intestinal system. Constipation is also a common cause for vomiting. Here is more information:
Sometimes, a cat can have acid reflux, which causes excess acid in his stomach to shoot up into his throat and burn it, then cause nausea. A good, over the counter remedy for this would be Pepcid AC (Famotidine), an acid reducer/controller. Give 1/4 tablet of a 10 mg. of Pepcid AC every 12 hours, preferably about 20 minutes before a meal. The tablet is very small, so 1/4 is tiny. You can usually hide it in a small piece of food or a Pill Pocket by Greenies--this is a 'treat' that cats love, which is shaped like a cylinder with a hole in the middle for the pill. It's soft and stretchy like Play Doh (the clay?), so you can rip off a small piece and wrap it around the 1/4 tablet and your cat should wolf it down quickly. Follow with some water.Here is more information:
Some cats are allergic to the protein source in their food (meat), so this may be a possible cause, as well. Certain manufacturers make foods with 'alternative' protein and carb sources, like Royal Canin, Natural Balance, Blue, and many others.
Ask your vet to do some blood work to find out more, but for the moment, try the Pepcid AC. At the vet visit, the doctor may want to give your cat an anti-emetic injection to alleviate the nausea.
Also, if hairballs are the problem, give your cat hairball get remedy like Laxatone or Petromalt as directed on the package. If he won't lick it off your finger, place a 'ribbon' of gel down on his forepaw, near his paw and he will lick it off, as cats can't stand 'sticky' on their fur. In addition, make sure to comb/brush your cat twice a day to remove excess 'dead' fur that he won't ingest while self-grooming.
I hope all will be well with your furry boy!
Please be so kind as to rate my answer with positive feedback, as that is the only way I receive recognition for my assistance. Thank you very much!Providing a positive rating will not end our conversation, should you need me for any follow-up. Simply click 'Reply' for clarification or additional information, if needed, at no additional cost.