820 ILCS 151/25: Prohibited acts.

(a) An employer shall not interfere with, restrain, or deny the exercise or the attempt to exercise any right provided under this Act.

(b) An employer shall not discharge, fine, suspend, expel, discipline or in any other manner discriminate against any employee that exercises any right provided under this Act.

(c) An employer shall not discharge, fine, suspend, expel, discipline or in any other manner discriminate against any employee for opposing any practice made unlawful by this Act.