The active ingredient in Febreze is hydroxypropyl beta-cyclodextrin (HPβCD). Procter & Gamble claims that these molecules bind hydrocarbons within the doughnut shape, retaining malodorous molecules, which reduces their release into the air and thus the perception of their scent. The original formula was developed in Plymouth, England. The use of a cyclodextrin as a sprayable odor absorber is patented by Procter & Gamble.
The product, initially marketed as a way to get rid of unpleasant smells, sold poorly until P&G realised that people become accustomed to smells in their own homes, and stop noticing them even when they are overpowering (like the smell of several cats in a single household). The marketing then switched to linking it to pleasant smells and good cleaning habits instead, which resulted in a massive increase in sales. Only after the product became well established in the marketplace did the marketing go back to emphasising odor elimination properties as well.
Veterinary toxicology experts working for the ASPCAAnimal Poison Control Center consider Febreze fabric freshener products to be safe for use in homes with pets. However, the package labeling indicates that the product is considered not safe around birds.