  We consider collisions of electric and magnetic polar molecules, taking the
OH radical as an example, subject to combined electric and magnetic static
fields. We show that the relative orientation of the fields has an important
effect on the collision processes for different fields magnitude at different
collision energies. This is due to the way the molecules polarize in the
combined electric and magnetic fields and hence the way the electric
dipole-dipole interaction rises. If OH molecules are confined in magnetic
quadrupole traps and if an electric field is applied, molecular collisions will
strongly depend on the position as well as the velocity of the molecules, and
consequences on the molecular dynamics are discussed.
