I totally understand your skepticism. I am always skeptical of stuff like this.
However, this much I know.....7 months ago when I first discovered I might have a yeast problem I did the spit test. I immediatly got tons of thick strings that hung down and stayed there, tons of floating specs in the water and a pool of thick sludge at the bottom. Now after 7 months of a hard core anti-candida diet and a number of the usual supplements I don't get any strings at all! Now what happens is there is a steady "snow shower" I like to call it. Small flakes of white slowly but steadily fall to the bottom of the glass and make a small pool of light sludge. I'm hoping that in few more months the "snow showers" will quit too.
I'm still not totally convinced that what I'm looking at is yeast, but there is no question my spit test has improved a lot in these last few months.