820 ILCS 148/25: 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 who 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.