  The scattering cross sections of charm mesons with hadrons such as the pion,
rho meson, and nucleon are studied in an effective Lagrangian. In heavy ion
collisions, rescattering of produced charm mesons by hadrons affects the
invariant mass spectra of both charm meson pairs and dileptons resulting from
their decays. These effects are estimated for heavy ion collisions at SPS
energies and are found to be significant.
