The crash happened just after 5:30 p.m. Sunday at the building on W. 20th Ave. Investigators say a 52-year-old Oshkosh woman was driving west in the post office parking lot when the medical condition caused her to veer to the left and crash into the building.
The driver was not hurt, but she was taken to the hospital to be checked out.
The SUV was badly damaged and had to be towed away.
Alcohol and drugs were not involved, police say. The woman was not given a ticket.