Roman Catholic Answer Excommunication is the most severe punishment that the Church hands out, it is indeed a punishment meant to bring an erring sinner to their senses bef…ore they lost their eternal salvation, from the Catechism of the Catholic Church: .
1463 Certain particularly grave sins incur excommunication, the most severe ecclesiastical penalty, which impedes the reception of the sacraments and the exercise of certain ecclesiastical acts, and for which absolution consequently cannot be granted, according to canon law, except by the Pope, the bishop of the place or priests authorized by them. (See Code of Canon Law , cann. 1332; 1354-1357) In danger of death any priest, even if deprived of faculties for hearing confessions, can absolve from every sin and excommunication. (see Code of Canon Law , can. 976).
Most excommunications are automatic, in other words, you automatically excommunicate yourself (this is called latae sententiae ) when you do certain things: apostasy from the faith, throwing away the sacred species, a person who uses physical force against the Roman Pontiff, a priest pretending to absolve an accomplice against the sixth commandment, a bishop who consecrates someone a bishop without a pontifical mandate, a priest who violates the seal of the confessional, any person who procures a successful abortion incurs an automatic excommunication. from Canon 1331 in the Code of Canon Law: .
An excommunicated person is forbidden: 1. to have any ministerial participation in celebrating the Eucharistic Sacrifice or in any other ceremonies whatsoever of public worship; 2. to celebrate the sacraments and sacramentals and to receive the sacraments; 3. to discharge any ecclesiastical offices, ministries, or functions whatsoever, or to place acts of governance. . ( Full Answer )