Sacramentals are sacred signs which, like the sacraments, express and have a special spiritual effect at the request of the Church. The sacraments prepare people to receive the most important effects of the sacraments and sanctify the various circumstances of life.
Sacramentals are first and foremost blessings (persons, food, things, places). Every blessing
is the glorification and prayer of God asking for His gifts. God the Father blesses Christians in Christ with “all kinds of spiritual blessings” (Eph 1: 3). The Church therefore blesses by shouting the name of Jesus and, as usual, by making the sacred sign of the cross of Christ.
The operation of some blessings is stable: they consecrate persons to God and allocate objects and places for liturgical purposes only. Among the blessings given to individuals — and they cannot be equated with sacramental ordination — are:
consecration of virgins and widows,
monastic vows,
the blessings of persons fit for some ecclesiastical services (lecturers, acolites, catechists, etc.).
Examples of items that receive bellsings include holy oils, liturgical vessels and clothing, bells, and so on.
When the Church publicly and authoritatively prays in the name of Jesus Christ for a person or thing to be protected from evil or to be freed from its authority, we call it exorcism. It was performed by Jesus, and the Church received from Him the power and task to cast out demons. In a simple form, exorcism is performed through Baptismal rites. Solemn exorcism, called “the great,” can be performed only by a priest with the bishop’s permission. Here one must act wisely and strictly follow the rules established by the Church. The purpose of exorcisms is the spiritual power entrusted to Jesus by the Church to drive out or influence evil spirits. Everything else is a disease, especially mental, that medical science has to take care of. So before committing exorcism, it is important to make sure that you are facing the presence of evil here, not disease.
(According to the Catechism of the Catholic Church)