  We have recently suggested a quantum action, which has the form of a
classical action and takes into account quantum effects via renormalized action
parameters. Here we apply it to quantum chaos. We study a system in 2-D with
weak anharmonic coupling ($V_{coupl} \propto x^{2}y^{2}$) being classically
chaotic. We construct the quantum action at finite temperature. We compute
Poincar\'e sections of the quantum action at that temperature and compare it
with those of the classical action. We observe chaotic behavior in both cases.
