It does stain your teeth.,
I used to use Plax. I loved the way my teeth felt so smooth and clean after brushing. My hygienist balked about Plax saying it was just flavored water and doesn't do my mouth any good. She suggested Crest Pro-Health because I was beginning to get gingivitis; in fact she said that if my inflammation was any worse I would have to get the dreaded "deep cleaning."
Shortly after beginning to use it I started to notice dark stains between my teeth. No amount of brushing or flossing helped.
When I went in for my next checkup my gums were better. It does seem to reduce gum inflammation. The fact that it actually worked in improving my dental health is the reason I gave it 2 stars instead of 1. I asked if there was any connection between Crest Pro-Health and the stains I noticed and she said that it does stain teeth but no more than coffee does. I don't think that is true because coffee never noticeably stained my teeth but this sure does. She said there were no other over the counter dental rinses that she thought were good enough to recommend. While I wasn't able to brush or floss the stain off my hygienist was able to remove it with polish. She did say that the rinse from Dental Herb Company was even better than Crest Pro-health rinse and doesn't stain teeth but the problem is that it is expensive, it is only available through dentists (they sell it), and it tastes bad. She said they don't usually recommend it unless patients have more advanced gum disease than I do but if the stains bother me I should consider it.
I have to give Crest Pro-Health props because it did work. I suppose having stained teeth is better than no teeth. I'll probably try the rinse that my dentist sells a try.