The best way to handle a cat urine odor problem is to prevent it before it happens.  Cats urinate out of their litter box for a number of different reasons, most of which are preventable.  Cats also tend to vomit for different reasons too, not just because they are sick. 

Preventing Cat Urine Odor

Cats can urinate out of the litter box for several reasons:

• Stress and Anxiety:  Cats experience stress and anxiety, just like people do.  Often, their way of dealing with stress is to urinate out of their litter box.  One of the most effective ways that you can reduce anxiety – and thus inappropriate urination – for your cats is with a product like the Feliway Diffuser.  The Feliway Diffuser plugs into a standard wall outlet and slowly releases a natural pheromone that resembles the pheromone your cat uses to mark her territory.  This has a calming effect on your kitty, reducing her urge to urinate.  I suggest the three-pack of diffusers for an average-sized home.
• Existing Cat Urine Odor:  Cats have a much better sense of smell than humans.  They can tell where there have previously been cat odor smells, and will repeatedly urinate there.  Often, this is because your cat has urinated in the same place over and over again without you cleaning it, but if you are not living in a brand new home, it can be because a previous owner had a cat that urinated in that spot.  If this is the reason your cat is urinating, you should clean the spot right away.
• Medical Issues:  If your cat is persistently urinating out of the litter box, particularly if he is not urinating in the same place all the time, he may be suffering from a urinary tract infection.  Symptoms of a urinary tract infection include a smaller amount of urine than normal, urinating in unusual places such as the bathtub or sink, blood in the urine, and yowling or obvious pain during urination.  If you suspect your cat may have a urinary tract infection, seek veterinary care.
• Litter Box Issues:  If your cat isn’t comfortable with her litter box, she won’t be as compelled to use it and may urinate on the floor instead.  The best litter box is the simplest litter box.  Either use a basic litter pan or a litter box with a shield.  Stay away from litter boxes with doors, or litter boxes that have an automatic scooping mechanism.  Doors and scooping mechanisms can frighten cats and make them less likely to use the box.

Preventing Cat Vomit

Aside from being sick, cats can throw up for several reasons:

• Hairballs:  Often, what we think of as cat vomit isn’t vomit at all.  It’s a hairball, which is simply hair that the cat ingested and is throwing up.  Often, you can prevent hairballs by simply brushing your cat’s hair to remove some of the excess fur for her.  If that doesn’t work, you can try a hairball remedy like chewable tablets or an anti-hairball gel, or your vet can prescribe anti-hairball food.
• Over-eating and Eating Too Fast:  Some cats can eat too fast, and as a result, will vomit up the food they just ate.  To slow your cat down, order a couple of large shooter marbles and put them in your cat’s food dish.  Shooter marbles are large marbles (about an inch or so in diameter) that are too large for your kitty to eat.  The idea is that the marbles force her to work harder to eat, thus slowing her down.
• Food Selection:  Cats need both wet and dry food to be healthy.  Unless your veterinarian has advised otherwise, make sure your cat is getting both dry and wet food.  As far as food selection goes, cat’s don’t like variety and can often have trouble digesting changing food.  Pick one kind of food and stick with it.  Don’t get a variety of food and alternate each time you feed him.