My father was addicted to them for almost 15 years....not addicted in a get-high way, but in that his sinuses couldn't function without them way. He started to have bleeding in his sinus cavities, so he had to go through a program to re-train his sinuses how to work on their own. I believe he had to use steroids? Or something similarly icky? and also saline nasal spray (which is not harmful for your sinuses). If you read the labels on these things, it does generally warn you not to use them for more than 3 days in a row.