In the instruction on the Liturgy of the Eucharist from the Congregation for Divine Worship and the Sacraments, titled Redemptionis Sacramentum, On Certain Matters to Be Observed or to Be Avoided Regarding the Most Holy Eucharist, these norms are cited:
• All experimentation with regard to the celebration of the holy Mass, as previously announced in 1970 and reiterated in 1988, is to cease (No. 27).
• Liturgical norms of a conference of bishops are to be submitted to the Congregation for Divine Worship for “recognitio, without which they are lacking in any binding force” (No. 28).
• “The community that gathers for the celebration of the Eucharist absolutely requires an ordained priest.” The priest is the proper celebrant and terms such as “celebrating community” or “‘celebrating assembly’ should not be used injudiciously” (No. 42).
• It is “laudable” to “have boys or youth … provide service at the altar after the manner of acolytes. … Girls or women may also be admitted to the service of the altar at the discretion of the diocesan bishop and in observance of established norms” (No. 47).
• Two paragraphs speak of the “matter” of the bread and wine used in the Eucharist and forbid the use of any substance other than those described (Nos. 48 and 50).
• Only the priest may recite the Eucharistic Prayer (No. 52). — Breaking the host at the time of consecration “is contrary to the tradition of the Church” (No. 55).
• “The reprobated practice … of altering or varying at will the texts of the Sacred Liturgy … must cease” (No. 59).
• It is illicit to omit or substitute the prescribed biblical readings (No. 62).
• A lay person may never give a homily (No. 64).
• The sign of peace, given just before Communion, must be sober in nature. “The priest may give the sign of peace to the ministers but always remains within the sanctuary as so not to disturb the celebration” (No. 72).
• “Anyone conscious of grave sin should not celebrate or receive the Body of the Lord without prior sacramental confession, except for a grave reason, when the possibility of the sacrament of confession is lacking” (No. 82).
• Communicants may receive the Body and Blood of Christ either standing or kneeling and “it is not licit to deny Communion” based on posture (No. 92).
• A host, when taken in the hand, “must be consumed by the communicant in the presence of the minister, so that no one goes away carrying the Eucharistic species in his hand” (No. 92).
• The communicant must not be permitted to intinct (dip) the host in the chalice (No. 104).
• Sacred vessels for the Eucharist must not be made from glass, earthenware, clay or other materials that break easily (No. 117).
• The extraordinary functions of the lay faithful: “Only out of true necessity is there to be recourse to the assistance of extraordinary minister in the celebration of the liturgy.” Such ministers, when they must be used, are never to be referred to as “Eucharistic ministers.” They are to be called “extraordinary ministers of holy Communion” and “not ‘special minister of holy Communion’” (Nos. 146-160).
• “The practice of those priests is reprobated who, even though present at the celebration, abstain from distributing Communion and hand this function over to lay persons” (No. 157).
• On the Lord's Day, holy Mass may not be substituted by an ecumenical celebration of the word or prayer services with Christians from their ecclesial communities (No. 167).
— Joan Lewis