The incident happened around 10:15 a.m. at the DuPage County Courthouse in Wheaton, officials said.
A man who attempted to leave the courthouse after being ordered for an evaluation during a court hearing was stopped by DuPage County Sheriff's deputies on an escalator landing.
The suspect resisted the deputies, and a physical struggle ensued, officials said. The man and at least one deputy fell down the escalator together.
Three deputies were taken to a local hospital as a result of the incident. Their condition were not yet known.
The suspect was taken into custody and charges are pending, DuPage County officials said.
No further information was immediately available.