Product review (5 stars): Passes the "sniff test".
I'm a medical professional and Mom of 3 kids. I researched this product extensively before using it. I thought I would share what I found: A clinical study was conducted in 2006, which showed this product was extremely effective at killing germs and mold in humidifiers (Journal of Water and Health, vol 4.2, 2006). Also, it's shown to be very safe and 100% natural (based on natural silver technology...the active ingredient in the cartridge is actually used in many drinking water filters found at the "big box" stores.) One point to mention: it doesn't remove minerals. If you get stains in your humidifier from iron in your water you'll need a demineralization product for that (or use filtered or distilled water). I use it and highly recommend it.