The effect of nasal douching in 40 patients with chronic rhinosinusitis was tested, and two different preparations compared: 19 receiving traditional alkaline nasal douche and 21 receiving a sterile sea water spray, in addition to their regular treatment. Douching per se improved endoscopic appearances (p = .009), and quality of life scores (p = .008). These measures did not change in a control group (n = 22) who received standard treatment for chronic rhinosinusitis, but no douche. There were significant differences between the two douching preparations in that the alkaline nasal douche improved endoscopic appearances but not quality of life, whereas the opposite was true for the spray.