This Brains On! episode focuses on asthma, exploring its causes, symptoms, and treatment. The show features a conversation between the hosts and two young sisters who have asthma, interspersed with listener questions and an explanation from a pediatric pulmonologist. The pulmonologist details how inhalers work by relaxing muscles around the airways, and discusses the genetic and environmental factors contributing to asthma. Listeners learn about asthma diagnosis methods and the evolution of asthma treatments. The episode concludes with a mystery sound segment and the Brains Honor Roll.