Cold atom gases have become on the best platforms to test quantum many-body physics in the last 20 years. They have prompted an interdisciplinary interest in cold atom systems, as they are relevant to other fields including nuclear, condensed matter and high-energy physics. Among the theoretical approaches to study cold atom gases, the functional renormalization group (FRG) has proved a promising tool to give a consistent and unified description of these systems. This is a non-perturbative approach based on the computation of the effective action by means of solving an RG equation. In this talk, I will give an overview of effective field theory and the FRG. I will focus the presentation on the properties of superfluid Bose and Fermi gases.