Not really effective.
I loved the idea of this, since I suffer from seasonal allergies.  When I opened the tablet, it has a nice herbal sent, but it did not work for me in the shower.  Maybe it was because I was using it in a tub shower, and not a shower stall, but when I put the tablet in the shower, (out of the  direct spray) I really didn't smell anything.
Rating: 3 stars