Cassy is a gray tabby who has this problem most often among my brood. Both fur kids enjoy cold cuts as treats, but Cassy must be limited to no more than two slices of those really thin sliced sheets -- the ones that look like you can read through that come about 10 -12 in a pouch designed to be one human sandwich worth? He sometimes gets too much with two slices, but three slices will tip him over for sure. He had a problem 3 years ago swallowing grass wrong, got sick at half hour intervals for about 6 hours and I rushed him to the vet. Since he loves grass, they still get it, but I cut it to no more than 3" in length [uh... 3" is 1/4' and 3' ~ 1 m, so 3" ~ 1/12m ... ~850 cm??? 3 inches is roughly the length of my forefinger, if 850 cm is a rediculous fingerlength just assume I've horsed up the math, okay?]

So, keeping him on hairball formula kibble, limit his cold cuts, and the length of the grass he eats reduces his 'upchuckies' to about once every other month. This is an amount I can live with and his vet isn't worried about... for what it's worth...