Do I need a letter of authorization to bring my grandaughter to the doctor?

Yes, is the short answer, a letter from a parent or guardian would be needed for standard medical care, however in an emergency you could take her to an ER and they would treat her if her life was in danger until the emergency was over but then a parent or guardian would have to authorize further treatment, a Notarized letter from a parent or legal guardian will suffice in most cases.}{