100 animales Coloring Mandalas for Your Mind & Body (size 8.5" x 11") Mandala coloring books and apps have the most effective healing power. Coloring can reduce negative thoughts, and unpleasantness. The special properties of mandalas are effective in reducing anxiety and stress. Sacred circles of a mandala have a magical healing power, which can have a recuperative effect. Renowned psychologist Carl Jung had his patients coloring mandalas 100 years ago as a tool for relaxation and self-discovery. So if you're feeling anxious, feel free to grab a coloring book to see if it makes you feel better. You've got science on your side - as long as you avoid pictures of sea turtles, apparently.