As Jennicat has said if your cat is throwing up frequently, the cat needs to see the vet. Especially if you are seeing yellow bile, not just regurgitated food.
If your cat is simply doing a scarf and barf, feed smaller meals, more often.
If your cat is having trouble with hair balls; daily grooming and a regular regimen (no more than twice a week) with hair ball remedy can control that problem.
Frequent vomiting is bad for kitty's teeth, the acid from stomach bile eats away at the teeth.
Vomiting is different from regurgitation.
Regurgitation is what comes up right after eating. Usually it is a "tube" shape, with is just the shape of kitty's esophagus, and the food is not at all digested. This can be from scarf and barf, hair ball trouble or a more serious blockage problem (hair balls can also cause blockages). If it happens every time the cat eats, veterinary attention is needed.
Vomiting, the food will be at least partially digested, and there will be more liquid in the vomit. Vomiting when there is no food at all, and is yellow and foamy, or blood, is a situation where vet attention is needed fairly quickly.
Sometimes hair balls can cause vomiting, even if you see no hair, or only a small amount. It can mean that the hair ball is lodged somewhere, and the cat cannot get it up, or pass it, with out some help. Again, veterinary attention may be required.