Vector meson propagation in dense matter

The properties of vector mesons in nuclear matter are discussed. Results for the momentum dependence of the $ρ$-meson self energy in matter due to $ρN$ interactions are presented, and consequences for the production rate of $e^+e^-$ pairs in hot and dense matter are discussed. I also examine the constraints imposed by elementary processes on the widths of $ρ$ and $ω$ mesons in nuclear matter, and conclude that in recent models the in-medium widths of these mesons are overestimated.