"Dark, Coarse and Bitter are good", because it is made from natural herbs."Dark" as we blend assorted natural herbs together without bleaching them to preserve its natural goodness."Coarse" as our herb powder will be swelled when absorbing water, giving the softness and high flexibility in cleaning teeth and gum smoothly without damaging teeth enamel."Bitter" as it is original taste of natural herbs.Altogether it helps clean your teeth and gum, eliminates bad breath, and safely decreases cigarettes, tea, and coffee stains, as well as keeps your breath fresh and clean all day long.Twin Lotus Herbal Toothpaste, Original formula. "Black is made from pure herbs." More than 10 kinds of natural herbal health care protection. Gums and teeth strong. Reduce tooth sensitivity. Helps your breath fresh. Can be cleaned up without damaging the enamel.Twin Lotus, Word of Mouth Products