  Properties of hypernuclei are studied in the context of a chiral Lagrangian
which successfully describes ordinary nuclei. Lambda-Sigma^0 mixing arises from
nondiagonal vertices in flavor space induced by the vector mesons and by the
electromagnetic field. The set of Dirac equations for the coupled hyperon
system is discussed. Results are presented for energy spectra and
electromagnetic properties of hyperons in the nuclear environment. Simple
estimates suggest that flavor mixing can lead to sizable changes in the
lifetimes of Lambda hypernuclei.
