  We present the beta functions of gauge and Yukawa couplings in general
four-dimensional quantum field theory, at four and three loops, respectively.
The essence of our approach is fixing unknown coefficients in the most general
ansatz for beta-functions by direct calculation in several simplified models.
We apply our results to the Standard Model and its extension with an arbitrary
number of Higgs doublets and provide expressions for all four-loop gauge
couplings beta-functions with matrix Yukawa interactions.
