Cats tend to hate smells that have a citrus, ammonia, pepper or cayenne scent, according to the University of Vermont. A cat also hates when the smell of its litter box is too close to its food, according to the Humane Society.
A simple solution to avoid accidents involves keeping the litter box in a separate area, away from the cat's food. When home owners wish to keep cats out of gardens or particular rooms in the home, pepper or cayenne can be spread around the area, as well as citrus- or ammonia-scented products, such as lemon oil. This will naturally and safely keep cats away.