The emergency room is packed as it often is at Stroger Hospital.
What is unusual is the high number of patients there because of the flu.
"This is pretty astounding," Dr. Tarlan Hedayati said.
"In general there's not a whole lot doctors can do for otherwise healthy patients," she said. "But when patients have pre-existing conditions that compromise their systems further, it can be serious."
Doctors say the symptoms are familiar: sore throat, cough, headache and fever. But they are often severe.
There's little they can do for most patients other than try to ease their suffering.
For the most part, the virus needs to run its course.
Doctors say it's not too late and probably a good idea to get the flu shot.
They also recommend using hand sanitizer to kill germs.