We are concerned with symmetric hyperbolic-parabolic systems with Korteweg-type dispersion. A new structural condition for the Korteweg-type dispersion is formulated, which allows to develop the dissipative mechanism of “regularity-gain type”. As an application, it is checked that several concrete model systems (e.g., compressible Navier-Stokes (-Fourier) -Korteweg equations) satisfy the general structural condition.