Garner, 43, met Doctor Samuel Nurko, director of the hospital's Center for Motility and Functional Gastrointestinal Disorders, reported People Magazine.
The two snapped a picture together that the hospital posted on Twitter, thanking the mom of three and wife of Ben Affleck for stopping by.
"A big thank you to Jennifer Garner for stopping by to meet with Dr Nurko to do research for an upcoming movie role!", they captioned the picture.
"Miracles from Heaven" tells the story of a young girl suffering from a rare digestive disorder who finds herself miraculously cured after surviving a horrible accident.