Article: When your cat hisses, back off. It's important that a cat not feel trapped or threatened, so don't corner it in a room. Just leaving a door open a crack so the cat knows it can run if it needs to can help soothe an anxious animal.  When approaching a nervous cat, go slow, and give it ample time to adjust to your presence and your scent. If your cat does run out of the room, don't chase it. That will only increase its anxiety. Make sure to warn children and guests to give your cat space, and to not try to force it to be sociable. Clean up any cat spray that might be in the home using a specially-formulated cleaner. If a neighbor cat is lurking outside a particular window or sliding glass door, use opaque contact paper or cardboard to cover the window so your cat can't see the intruder. If your cat is an indoor animal, you can use cayenne pepper or a specially formulated cat repellent around the perimeter of your yard to try to keep other cats from intruding. If your cat is stressed out by a new baby or pet, time will often help, but you can further assist your cat by providing him with ample resources and places to hide.  Make sure the cat has at least one place to perch that will keep him out of reach from any would-be pesterers, like a tall climbing post or kitty shelf. If you have more than one cat, make sure that there are enough litter boxes, food dishes, and water bowls for everyone. Cats are much happier when they don't have to share. Spend more time playing with your cat, and try introducing new ways to stimulate him. Hide little treats around the house where your cat can find them, and never underestimate the therapeutic power of catnip. There are a number of products on the market that help soothe stressed cats by releasing soothing pheromones into the air. Check with your vet or local pet store for a specific recommendation. These products can be pricey, but they may be worth it. If you still can't figure out how what's bothering your cat, or how to fix it, have your pet checked out by the vet. There may be something going on physically with the cat that you can't see, or the vet may have suggestions for medication or other treatments that can help soothe your distressed animal.

What is a summary?
Give your cat space and time to calm down. Remove irritants from your cat's environment. Provide adequate resources and refuge for the cat. Buy some new toys. Try a pheromone spray. Consult your veterinarian.