Abstract: The static mixer has a polymorphic structure that can be used for mixing or homogenizing a fluid medium. The mixer has at least two sections arranged in a tube one after the other in the longitudinal direction. Baffles of the first section that are effective to promote mixing redistribute the medium to be mixed largely globally over the entire cross-section of the tube. Baffles of the second section that are effective to promote mixing effect largely local mixing in partial regions, which in each case contain only one part of the tube cross-section. The baffles of both sections have the same or approximately equally large hydraulic diameters.