Optical activity of atomic medium with interfering laser induced continuum structures is studied theoretically and
illustrated by the example of hydrogen. The optically active region in the atomic spectrum is scanned by linearly
polarized probe field whose polarization properties are changed by the medium. Analytical equations for acquired
ellipticity and polarization plane rotation are obtained. They demonstrate that the optical activity is a non-trivial function
of the parameters of the driving laser fields. Numerical results are presented for the VUV probe radiation with two
circularly polarized lasers, coupling the hydrogen <i>Ep</i> continuum with the 2<i>s</i> and the 5<i>s</i>, 5<i>d</i> states, respectively.