It's not uncommon, says Dr. Guglielmino, for a cat to "upchuck" a hairball once every week or two, and that's nothing to worry about. However, if your cat is lethargic and for more than a day or so, or has had repeated episodes of unproductive retching, you should consult your veterinarian without delay.
But if some hair stays in the stomach, it can form a hairball
Anyone who has cats has probably seen a hairball or two. Do you know why hairballs form, or how you can help prevent and treat them? We’ve got some helpful tips for you and your cat.
Usually, your cat will vomit the hairball to get rid of it
Is a hairball a different item from regular regurgitation of food? I think that if you can still recognize it as food, then it was regurgitated. A hairball has hair all through it. In the discussion, it sounds like people are saying that it is all the same thing — related to what type of food they are eating. I have tried all kinds and my cat still throws up frequently after eating.
Cats and Hairballs | Remedies for Hairballs in Cats | petMD
Some cats are much tidier than others and groom a great deal. These cats tend to have more hairballs than sloppier cats. Johan is a very relaxed cat and does not made a great fuss over his appearance and he rarely has hairballs.A cat that hacks and goes through the motions of bringing up a hairball but can't seem to get it out might need help. If this goes on for longer than expected, or if your cat is not eating or is listless or if he has diarrhea or constipation you should pack him off to the vets.The type of hair a cat has influences how many hairballs he produces. Long hair cats usually produce more hairballs simply because they have more hair. In the case of my Winston this is not the case. His hair is not prone to matting and he rarely seems to get hairballs.Don’t panic. It is rare for a cat to need a hairball surgically removed. In most cases, adjusting the diet and adding in a healthy oil to their diet will help relieve the issue. What you want to do is use extra virgin coconut oil (organic is best) and allow your kitty to eat up to a tablespoon of this a day until the hairball is passed through either end. If they don’t like it, just melt it down and add some to each meal. If you don’t have coconut oil, pure olive oil is the second best option. For very picky cats, butter can be used but it should never be given in excess or for more than a few days. It has to be pure butter as well. Never give your cat spreads of any kind.