The Holy Eucharist, more commonly known as communion, is a central part of the Catholic Mass. Catholics eat bread and drink wine during every worship service. They do so in recognition of their belief in the possibility of salvation for all Christians by the death and resurrection of Jesus. An ordained priest must bless the bread, which is a wheat wafer, and wine, through prayer. This blessing transforms the bread and wine into a holy substance, according to theology. As with most things in the Catholic faith, communion is a custom that follows regulations set by the pope and his bishops.

Eligibility

Only certain persons have a right to participate in the communion ritual. In general, recipients must be baptized Catholics in good standing. Catholics conscious of any grave sin, such as violating one of the Ten Commandments of the Bible, must confess this sin to a priest before partaking of communion. Orthodox Christians, Polish National Catholics and Assyrians of the East are also eligible to participate, because they essentially practice the same faith. Catholics exclude other Christians, including Protestants, from the ritual. Nevertheless, any Christian may receive communion with prior approval from a priest.

Beliefs

Catholics understand Jesus to be present during communion. Each communion ceremony is a recreation of the crucifixion, the moment Christians believe Jesus gave his life for the salvation of humankind. Before receiving their first communion, all Catholics must profess knowledge of the real presence of Jesus in the ceremony.

Substance

According to regulations, the communion wafer must consist of only two substances, wheat and water. Any non-wheat wafer is invalid for a Catholic-sanctioned religious service. People who, for dietary reasons, cannot digest wheat may abstain from this part of the service. The drinking of the wine is expected, however, of such individuals. If unable, for some reason, to drink wine, then the person will receive mustum, a mixture of fresh grapes. Anyone can hold a silent communion of reflection in their seat while the others partake of the bread and wine at the altar.

Transubstantiation

The ability of ordained Catholic priests to turn bread and wine into Jesus is transubstantiation. During Mass, the priest prepares the communion meal before the people assemble before the altar. The priest blesses the wine and bread through the communion, or Eucharistic, prayer. According to Catholic theology, at this time the bread and wine mysteriously transform into the body and blood of Jesus.