Mamotte! Lollipop is an anime series based off of the manga with the same name.
Nina is an ordinary girl that likes eating cakes and sweets and hanging out with her friends. But one day, while eating candy, she accidentally swallows the Crystal Pearl while eating cake with her friends. It turns out that the pearl is part of a test for student magicians. In order to get the pearl back, Zero and Ichi, two young magicians, must get a special medicine for her, while protecting her from other magicians who will try to get the pearl any way they can.
The show ended a year ago, but a sequel titled Madotte Mamotte! Lollipop is in production.