  The Casimir effect for parallel plates within the frame of five-dimensional
Randall-Sundrum model with two branes is reexamined. We argue that the nature
of Casimir force is repulsive if the distance between the plates is not
extremely tiny, which is not consistent with the experimental phenomena. We
also point out that the estimation of the separation between the two branes, by
means of Casimir effect for two-parallel-plate system, is not feasible, in
contrast to another recent study.
