The suit contends the alleged culture puts prisoners "under a constant risk of life-threatening violence," the Chicago Tribune reported.
The lawsuit was filed by the MacArthur Justice Center at Northwestern University. The Tribune said the suit includes sworn statements from nearly 100 inmates, and names Cook County board President Toni Preckwinkle, Sheriff Tom Dart and other county officials.
The suit alleges, among other things, that jail officers often slam people to the floor, "stomp, kick and punch them"; officers assault inmates who request mental healthcare or "attempt to complain to higher-ups about living conditions"; and officers fail to intervene in fights and "order men to attack and beat each other."
The suit alleges "racist and homophobic bravado" is common among officers and their supervisors, the Tribune said.
There was no immediate comment from officials.