  In this work we explicitly show that the perturbative unitarity of analytic
infinite derivative (AID) scalar field theories can be achieved using a
modified prescription for computing scattering amplitudes. The crux of the new
prescription is the analytic continuation of a result obtained in the Euclidean
signature to the Minkowski external momenta. We explicitly elaborate an example
of a non-local $\phi^4$ model for various infinite derivative operators.
General UV properties of amplitudes in non-local theories are discussed.
