  Theories with higher derivatives involve Ostrogradski ghosts and can be
viewed as a very serious problem during quantisation. To cure it, we have
considered the properties of antilinearty found inherently in the non-Hermitian
Hamiltonians. Owing to the existence of antilinearity, we can construct an
operator, called the $V$-operator, which acts as an intertwining operator
between the Hamiltonian and it's hermitian conjugate. We have used this
$V-$operator to remove the linear momenta term from the higher derivative
Hamiltonian by making it non-Hermitian on the first place via an isospectral
similarity transformation. The final form of the Hamiltonian is free free from
the Ostrogradski ghosts under some restriction on the mass term.
