That's what my vet said about my cat, Taro.
She says she has a cat that vomits twice a week, and seemed to see nothing wrong with it. If anything, she seemed bemused that I had rushed him in after he vomited twice in a two-week period.
This was after the first episode of repeated vomiting, several weeks earlier, when she discovered that he had an intestinal blockage and he had to have an enema.
He takes Cat Lax every day now, although this works out really well as far as he's concerned because he loves the taste.
I asked if there was a special diet I should put him on, and she shrugged and said I could try hypoallegenic food. They sell some at the office, but the price made me gulp. I would have to change the entire household over to this diet because he would eat everybody else's food. (Taro will eat anything, he's like a Roomba.) Normally I will spare no expense for my kitties' health care, but that diet would really bankrupt me.
So I'm trying for an intermediate option, one that's not hypoallergenic but is higher-grade. Maybe we'll get really lucky and it will be an allergy to cornmeal or meat by-products that's causing it. Right now I'm trying Nutro Max, which he really seems to like, but the other cats won't eat. Also, the first time I fed it to him, he threw up the next day.
I'll keep working on finding a diet that all my cats can live with. I'm going slow, still feeding them the old stuff mostly so the change isn't a shock to their systems. Hopefully it will work. Otherwise, I guess I'll just have one of those cats that vomits.