We present a simple theoretical approach to treat the interaction of a laser field with a semiconductor system, in which the effect of the laser field is incorporated within a renormalization of the semiconductor effective mass. As an application, we discuss the effects of laser dressing on the transition energies between the 1s- and 2p(+/-)-like states of hydrogenic donors in GaAs-Ga1-xAlxAs QWs, in the presence of an external homogeneous magnetic field. It is shown that the modifications on the intradonor transitions due to weak intensity-laser dressing may be as important as the effects of a strongly applied magnetic field. (C) 1998 Elsevier Science Ltd. All rights reserved.10713134