  We show that an extremal Gibbons-Maeda-Garfinkle-Horowitz-Strominger black
hole may act as a particle accelerator with arbitrarily high energy when two
uncharged particles falling freely from rest to infinity on the near horizon.
We show that the center of mass energy of collision independent of the extreme
fine tuning of the angular momentum of the colliding particles. We further show
that the center of mass energy of collisions of particles at the ISCO
($r_{ISCO}$) or at the photon orbit ($r_{ph}$) or at the marginally bound
circular orbit ($r_{mb}$) i.e. at $r \equiv r_{ISCO}=r_{ph}=r_{mb}=2M$ could be
arbitrarily large for the aforementioned spacetimes, which is different from
Schwarzschild and Reissner-Nordstr{\o}m spcetimes. For non-extremal GMGHS
spacetimes the CM energy is finite and depends upon the asymptotic value of the
dilation field ($\phi_{0}$).
