The Department of Child and Family Services (usually referred to by its acronym of "DCFS") is a fictional organization in the Chicago universe. Its concept is based on that of similar real-life organizations.
DCFS is informed when a hospital staff member suspects abuse or neglect of a child, and in other situations where they are legally obligated to do so, such as parental kidnappings.
In Chicago Med, the department is usually represented by Madeline Gastern.