  This chapter overviews the principles of the spontaneous emission rate
increase, that is the Purcell effect, in relation to the photonic parity-time
(PT) symmetry. Being focused on the system of coupled PT-symmetric optical
waveguides, we consider behaviors of the Purcell factor in PT-symmetric and
broken-PT-symmetric regimes. Surprisingly, exceptional points in a coupled
waveguide do not influence on the Purcell factor.
