I've used a lot of harsh toilet cleaners in the past where the fumes were quite dangerous but with the Harpic Power Plus the fumes were just bearable, not as bad as the other brands. I can tell you that after trying so many different kinds of toilet cleaners and giving the Harpic product a try that my toilet bowl looks brand new and sparkles white whereas before it was dull and stained horribly. I had expected this to another passable failure like the others but after only using one box and following the instructions stated on the product all of the toilet stains disappeared. I am one happy customer, as there were no other faults to this toilet cleaner other than its strong smell, it's easy to apply and features a thick formula allowing me to better cover the entire surface of the bowl and disinfected any germs concerning that area. Harpic's claims of being 5x more powerful than bleach and will remove even the toughest stains with just one application is all true. I will keep using as recommended as this is the only product that has properly cleaned my toilet.