It's Dr. Lily to the rescue!

The second book in the Lily series, with over a million copies sold!

After witnessing a car accident and helping a little boy who was hurt, Lily embarks on a mission to become a "great doctor"--and no one's going to stop her! Lily starts watching medical shows on TV, checks out health books at the library, and signs up for a Taking Care of Your Body class for girls. As usual, Lily goes overboard, and it's not long before she's trying to change the Girlz Only Club into a health class--fitness plans, label reading, exercise, and more. However, her friends aren't too thrilled about her newfound passion, and when they stop wanting to be around her, Lily has to choose. In the end, Lily learns and important lesson about friendship that she'll never forget.