Officials said no serious injuries have been reported.
Airport spokeswoman Victoria Lupica said US Airways flight 720 had taken off from Charlotte, N.C. bound for Rome, but local officials were informed just before 10 p.m. Tuesday that the plane was diverting to Philadelphia after some people reported symptoms of nausea.
Lupica said airport police, fire and emergency crews responded and the flight landed safely.
The fire department said five people were taken from the airport's Terminal A to the Hospital of the University of Pennsylvania, where their condition was not immediately available.
Airline representatives did not immediately return a call seeking comment.