  We study the one-loop covariant effective action of Lifshitz theories using
the heat kernel technique. The characteristic feature of Lifshitz theories is
an anisotropic scaling between space and time. This is enforced by the
existence of a preferred foliation of space-time, which breaks Lorentz
invariance. In contrast to the relativistic case, covariant Lifshitz theories
are only invariant under diffeomorphisms preserving the foliation structure. We
develop a systematic method to reduce the calculation of the effective action
for a generic Lifshitz operator to an algorithm acting on known results for
relativistic operators. In addition, we present techniques that drastically
simplify the calculation for operators with special properties. We demonstrate
the efficiency of these methods by explicit applications.
