  The properties of vector mesons in nuclear matter are discussed. Results for
the momentum dependence of the $\rho$-meson self energy in matter due to $\rho
N$ 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 $\rho$ and
$\omega$ mesons in nuclear matter, and conclude that in recent models the
in-medium widths of these mesons are overestimated.
