Non-invasive continuous positive airway pressure (CPAP) is a useful tool for managing patients with acute respiratory failure. The head helmet is a relatively novel interface that is as effective as the traditionally employed face-mask in delivering CPAP and can possibly be characterized as better for the patient's tolerance and, consequently, a longer duration of treatment. This review focuses on the main properties of the helmet and the issues related to its use, as shown by the physiological and bench studies. Clinical experience, both personal and reported in the literature, for the treatment of both cardiogenic and non-cardiogenic pulmonary edema is reviewed as well.