Abstract
We discuss the results of our detailed study of the impact of two giant protostellar outflows (HH 300 and HH 315) on their parent molecular clouds. Our results show that both of these outflows have modified their respective parent clouds' density and velocity distributions at parsec-scale distances from their source. We also compile and study a sample of 5 (two from our study and three from the literature) giant molecular outflows and their host clouds. The data from our small sample indicate that a ``typical'' giant molecular outflow in a relatively small molecular cloud (mass less than about 80M[ sun ]) has a kinetic energy comparable to (or larger than) the turbulent energy and the gravitational binding energy of its parent cloud. Thus, in some cases a single giant protostellar outflow may have a profound effect on the evolution and fate of its parent cloud.
