The patient checked into the hospital's emergency room Monday with a high fever and gastrointestinal problems. The man had recently returned to the United States from a West African country where Ebola had been reported.
The hospital issued a release Wednesday saying the male patient was in stable condition and was improving.
The U.S. Centers for Disease Control and Prevention in Atlanta, near where two other Americans are being treated for the deadly virus, confirmed the man didn't have Ebola.
Both Dr. Kent Brantly and Nancy Writebol were being treated for Ebola at Emory University Hospital in Atlanta. The two were treating Ebola patients in Liberia with aid group Samaritan's Purse when they were diagnosed with the virus.