Product review (1 stars): Be careful!!!
I started using this product nights in my humidifier fall 2009. Came down with acute bronchitis Dec. 2009; had to go to emergency room in Jan. 2010 and subsequently was on oxygen for 10 days. Took 7 weeks to get rid of the bronchitis [and cost me a lot of money]. Guess how I contracted the bronchitis -- the bacteriostatic ingedient in  this product: dimethyl benzyl ammonium chloride. [Yes, we were able to isolate this variable in my environment.] Research this ingredient, and you will see that it can indeed induce bronchitis. So be very careful how you use products that contain it!!