Abstract: A hydrodynamic approach with a nonequilibrium equation of state is developed to describe the emission of protons and pions formed in collisions of heavy ions of intermediate energies, an amendment for the microcanonical distribution is taken into account, and the contribution of the fragmentation process is included. Experimental data of Institute of Theoretical and Experimental Physics (Moscow) on collisions of ¹²C nuclei with a beryllium target at energies of 1–2 GeV per nucleon for carbon nuclei with proton emission are considered. It is shown that these data can be described within a hydrodynamic model for high-energy cumulative region of the proton spectrum, taking into account the contribution from ion fragmentation for the soft spectral region within the framework of the statistical fragmentation model. The calculated double differential cross sections for pion emission at these energies agree with the available experimental data.