Try a little at first, like maybe a 1/2 teaspoon or so, and give it maybe an hour to see if your boy holds it down/doesn't vomit it back up.
Kitten Vomiting Foam
Pictures. Learn the causes of cat vomiting foam, foamy blood, clear liquid lethargy, panting, not eating, shaking, treatment and prevention. If your cat is young and she does not know when to stop eating her kibble, vomiting up white foam is the best way for her to.
Dog vomiting yellow bile, yellow foam, with diarrhea, and ... from www.dogscatspets.org
The cat usually only vomits once or twice with each occurrence. Learn the causes of cat vomiting foam, foamy blood, clear liquid lethargy, panting, not eating, shaking, treatment and prevention. If you see your cat acting fine, playful.
If our kitten vomits white foam and we have not dewormed it internally it could be infested with internal parasites.
If your cat is vomiting foam, it's likely to be bile. Some kittens suffer from adrenal gland disease in which they cannot produce enough cortisone. If the vomit contains undigested food pellets, you can tell that is not the kind of vomit to look for. They seemed to curl up when they hit the air.
