The scientific basis for inhalation therapy in mechanically-ventilated patients is now firmly established. A variety of new devices that deliver drugs to the lung with high efficiency could be employed for drug delivery during mechanical ventilation. Encapsulation of drugs within liposomes could increase the amount of drug delivered, prolong the effect of a dose, and minimize adverse effects. With improved inhalation devices and surfactant formulations, inhaled surfactant could be employed for several indications in mechanically-ventilated patients. Research is unraveling the causes of some disorders that have been poorly understood, and our improved understanding of the causal mechanisms of various respiratory disorders will provide new applications for inhaled therapies.