Garr's career began to slow in the late 1990s after a neurologist informed her that symptoms she had been experiencing for many years were those of multiple sclerosis. In film, she appeared in minor supporting roles, including a witch in the children's film "Casper Meets Wendy" (1998) and the mother of Michelle Williams in the political comedy "Dick" (1999). This was followed by an uncredited role in Terry Zwigoff's "Ghost World" (2001). She also provided the voice of Mary McGinnis in two Batman animated films: ' (1999), and ' (2000).