Asthma is a common breathing disorder in cats, decreasing quality of life and sometimes causing death. In cats with certain genetic backgrounds and other environmental influences, inhaling what should be harmless airborne allergens triggers inflammation and constriction of the airways. These pathologic changes are, in part, thought to be mediated by complex crosstalk between nerves in the lung and immune cells. One class of mediators, the tachykinins, has not received much attention in veterinary medicine. However, there is evidence in experimental rodent asthma models and in humans with asthma that blocking the action of tachykinins with selective drugs can be a helpful treatment. One such drug, maropitant, already safely and widely used to treat vomiting in cats, may also be useful for asthma in pet cats. A prospective, randomized, placebo controlled study in experimentally asthmatic cats will determine if maropitant can reduce airway inflammation, clinical signs, and airway constriction. These results may provide a safe and effective alternative treatment to current therapies for pet cats with asthma.