When a cat vomits on carpet or furniture, the trick is to clean it up as soon as possible. Catch it early and you'll be able to remove it with nothing more than a little soapy water. When this isn't possible, just remember that time isn't on your side. Even if vomit stains have dried, they might not have set into the fibers.
Removing the Stain
If the vomit has a yellow tinge it probably contains bile. The acid content in bile can cause serious harm to carpets and fabric. Even if the stain disappears after cleaning it with soapy water, deodorize it with a white vinegar cleaning solution to ensure it's adequately disinfected.
Remove the large solids. Scoop as much of the vomit as possible with a spoon or spatula onto a paper towel, and then scrape away the smaller pieces with a knife. Discard immediately.
Run the item under cold water to flush out the excess, if the accident occurred on an item of clothing, sheet or piece of fabric that can be moved. If it's on carpet or upholstery, blot the stained area with a wet cloth or paper towel.
Pour 1/2 cup of white distilled vinegar and one tablespoon of mild dishwasher liquid into a mixing bowl. Whisk the solution until it starts to foam.
Scoop the foam from the top of the solution with a spoon, and place it over the stain. Let it sit for a up to 5 minutes. Wipe the stain in a circular motion with a damp cloth or paper towel. Repeat the entire process several times.
Vacuum the stain after it has dried to remove any excess vomit. Don't worry about the concentrated vinegar smell. It won't linger for too long.
Neutralize the Odor
To neutralize any remaining odors sprinkle a fine layer of baking soda or borax over the stain, and then brush it in with an old toothbrush. Let the powder sit overnight and then vacuum it up in the morning. If there's still baking soda or borax on the carpet or fabric, clean it up with a damp sponge and then lay a dry towel over the top to absorb the moisture before vacuuming it again.
While homemade products can take the place of store-bought cleaners, for particularly difficult cat vomit stains you may need something a little stronger. If you need to use a commercial cleaning product, make sure it contains an active enzyme. Enzyme products help to digest the proteins in the vomit to make it easier to remove.