Feliway Friends contains a synthetic copy of the calming pheromone of cats (CAP), which female cats release from glands in the mammary area when they have kittens. This pheromone creates a harmonious bond between cats. Feliway Friends is the first product on the market that has been proven to reduce tension and conflict between cats. The synthetic pheromones in Feliway Friends promote harmony among cats, while the synthetic pheromones in Feliway Classic provide a sense of security in the cat's home environment.