  We study the production of non-strange mesons in proton-proton scattering
reactions within an effective model of mesons and baryons with global chiral
symmetry. The model includes the nucleon ($N$) and its chiral partner
($N^{\ast}$) and their couplings to the $N_{f}=2$ multiplets of (pseudo-)scalar
and (axial-)vector mesons. Results for the production of $\omega$ and $\eta$
mesons are presented.
