Cats interact with each other and with the world around them through pheromones, a type of chemical messenger that they naturally release. Each cat produces its own pheromones to send messages to the environment and to other cats. Feliway Optimum is a blend of cat pheromones that will create messages of well-being and calmness in your cat with unprecedented intensity. You can use Feliway Optimum at any life stage of your cat, from kitten to senior cat. Feliway Optimum is only perceptible to cats. It has no effect on humans or other household animals, such as dogs.