The Eucharist in the Catholic Church is the celebration of Mass, the Eucharistic liturgy. The term Eucharist is also used for the bread and wine when transubstantiated(their substance having been changed), according to Catholic teaching, into the body and blood of Jesus Christ. “At the Last Supper, on the night he was betrayed, our Savior instituted the Eucharistic sacrifice of his Body and Blood.” (CCC 1323)