Eucalyptus oil and other leaf extracts may be useful, but it is not a good tree to have near your home. There are 2 reasons:
Two things @ eucalyptus
1. They are not so resistant to high wind pressure/storms gale etc. They will often be uprooted by a sudden strong wind and damage home, car etc(may even kill men).
2. They absorb a lot of ground water. You plant a lot of eucalyptus around a pond, and as the eucalyptus grows it may dry up the pond if the pond is not substantially below the water table level.