Humidified oxygen is widely administered in hospitals and EMS vehicles and this is presumed to alleviate nasal and oral discomfort in the non-intubated patient. Humidification of supplemental oxygen is commonly delivered by bubbling oxygen through either cold or warm sterile water before it reaches the patient. However, the effect on patient comfort is negligible. Bubble humidifiers may, however, represent an infection hazard and should not be used.