Excessive oxidants released by activated inflammatory cells and persisting infections are considered the main mechanism of damage of respiratory epithelium in CF.Glutathione (GSH) represents the first-line defence of the lung against oxidative stress-induced cell injury; however, a depletion of its levels has been observed in the airways of patients affected by CF. In vitro studies have showed that CFTR protein plays a pivotal role in transmembrane glutathione transport. Therapeutic approaches with inhaled GSH could improve the reduced lung antioxidant capacity in order to counterbalance the oxidant stress linked to the chronic airway inflammation and bacterial infection.