Previous researchers have questioned the use of tap versus sterile water with oxygen humidification as well as the optimal frequency of changing systems based on contamination rates . The impact of humidification on patients’ symptoms also has been investigated with high and low flow oxygen administration. Campbell et al questioned whether humidification was necessary for patients receiving oxygen at the rate of 5 L/min or more, and Estey studied 34 patients who received either dry or humidified oxygen therapy of 4 L/min or less. No differences were found in either study in the subjective complaints of patients receiving humidified versus nonhumidified oxygen, and it was concluded that routine humidification of oxygen by nasal cannula could not be justified for nonintubated patients receiving high or low flow oxygen. However, limitations in both study designs included small sample sizes, quasi-randomization and/or a nonblinded method for oxygen administration. Despite the scarcity of evidence regarding the effectiveness of humidification as a therapeutic intervention, some experts believe that, for patients with chronic chest disease and superimposed infection, supplemental humidity may help defective clearance mechanisms, and its use is well established for intubated patients receiving dry anesthetic gases . The purpose of this study was to determine the clinical effects of humidified versus nonhumidified low flow oxygen administration on the subjective symptoms of patients. Safe online shopping for drugs: Buy Cheap Claritin to make your drugs cheaper.