  Functional renormalisation group approach is applied to a system of kaons
with finite chemical potential. A set of approximate flow equations for the
effective couplings is derived and solved. At high scale the system is found to
be at the normal phase whereas at some critical value of the running scale it
undergoes the phase transition (PT) to the phase with a spontaneously broken
symmetry with the kaon condensate as an order parameter. The value of the
condensate turns out to be quite sensitive to the kaon-kaon scattering length.
