Small GTPases of the Rho family regulate a wide variety of cell functions. In this review, we briefly describe the biological activities of Rho GTPases. Using the Rac-regulated NADPH oxidase as an example, we discuss possible regulatory points that might be exploited for drug development. Finally, we explore strategies for specific targeting of Rho GTPase-regulated signaling pathways. © 2001 Prous Science. All rights reserved.