The concentrate has been used for some time, first as in the instructions referred to 5 drops per 15 ml of water, 2 times a day, followed by slightly increases the number of drops. Brown liquid itself, confused that when 30 seconds poloschesh teeth and gums appear brown flakes. Some stick to the teeth, so you have more time to walk with a toothbrush and rinse the mouth with water. Gums really are better, this does not take away. But the color and these flakes are confused. Hopefully this will not affect the enamel) And another warning - the sharpness is present in the concentrate, but you get used to it)