It is toothpaste containing baking soda.

When I first used it, I thought it wasn't very good because it tasted too salty and didn't foam well, but

As I kept using it, my mouth actually felt fresher, and it seemed to have a whitening effect as well.

After using this, when I tried a different toothpaste, I thought it tasted bland and wasn't very good.

I am on my second bottle now, and I think I will keep using it.