Generally, gas pain in cats is caused by either an overall inadequate diet, the ingestion of improper foods, or the cat "wolfing" its food and swallowing too much air. Though it is important to treat the symptom of gas pain for the comfort of your kitty, it is even more important to treat the cause.
How to Treat Gas Pain
Purchase simethicone from any pharmacy or most supermarkets. Simethicone is an over-the-counter gas reliever sold under the brand names Mylicon or Gas-X. For cats, it is best to use the liquid, infant form containing no dyes, but if your are more comfortable giving your cat a pill, the adult form of the medicine is available as a pill or softgel.
Give your cat 1 to 2 milliliters of infant simethicone every hour until symptoms desist. Hold kitty's head firmly and insert syringe into the mouth between the teeth and the cheek. You want to release the liquid into the cheek as far back toward the jaw as is comfortable.
Hold the cat's mouth shut for a moment to insure the medicine gets swallowed rather than spit out. You can stroke the cat's throat to try to entice her to swallow.
Get your cat to move around. Exercise will help expel gas bubbles in her stomach, whereas leaving the cat to sit hunched up will only make her pain worse. Entice kitty to play a game, chase string or anything else you can do to keep her moving.
Change Your Cat's Diet
Stop feeding your cat "human food." Cats are obligate carnivores, and are not able to properly digest dairy, grains or vegetables. Also, food that is even moderately spoiled can cause stomach problems in cats.
Feed your cat a high-quality, high-protein canned food. Most supermarket brands are mostly filler and by-product. As most cats do not drink enough water, dry kibble may become a dehydrated mass in the stomach, and a dry-kibble-only-diet may lead to kidney or urinary tract problems.
Change a cat's diet slowly by starting with just a little of the new food in place of the old and gradually increasing the ratio of new food to old over a couple of weeks' time. Sudden changes in diet can cause stomach upset for your pet.
If Your Cat Eats Too Fast
Provide three to five smaller meals throughout the day as opposed to one or two larger meals.
Feed your cats apart from each other if you have multiple cats. This will reduce competition for food.
Place ping pong balls in your cat's bowl. The cat will have to slow down and take a moment between bites to push aside and work around the ping pong balls, and the ping pong balls are too large for the cat to accidentally swallow.