Flouride is necessary to strengthen teeth, and if you happen to live in an area that doesn't have fluoridated drinking water, or if you aren't getting some other systemic source of fluoride, then you really need to get it topically - via toothpaste and/or a mouthrinse. ACT is really amazing stuff for this end. If you call them up, they will send you all the studies that they did on their mouthwash. Some people prefer listerine or scope - but many often complain that these mouthwashes are extremely harsh in taste (I am one of the many). The people here at UB's dental school who did many of the studies concerning the various mouthwashes conclude that ACT IS the best. Not that that really means anything...it's just a minority consensus from one of the top research schools in the country.