I have been on Singulair for 2 1/2 years for asthma. Although it didn't totally get my asthma under control, it lessened it a lot. (it took me getting on Advair along with Singulair to almost completely cut my dependence on albuterol inhalers to stop my asthma attacks.) A few months back I was feeling so great that I wasn't having any attacks that I decided I could stop taking Singulair. BIG MISTAKE. Within 5 days my wheezing had returned, I had a significant asthma attack that landed me in the emergency room. Moral of that story: DON'T QUIT YOUR MEDS UNLESS YOU CONSULT YOUR DOCTOR. I do have the dry mouth side effect but that's a small price to pay to be able to breathe without struggle. I live in a large city where I'm always subjected to pollution and I thank God every day for Singulair and Advair.