Dealing with separated and divorced Catholics and the Eucharist, the One Bread One Body document says that "being separated or divorced does not in itself mean a person may not receive Holy Communion".
However, it continues that "the Catholic Church has reaffirmed her practice of not admitting to Holy Communion people who have divorced and remarried".
Discussing the varied nature of congregations at Mass, it says: "There are Catholics who are in new relationships established after one or both partners have suffered the trauma of breakdown in their marriages and who are unable therefore to participate fully in the Eucharist they celebrate.
"Some Catholics present may be in irregular marriage relationships and for that reason may not go to Communion."
In summary, divorced and remarried Catholics, Catholics in second relationships (after marital breakdown) and Catholics in "irregular marriage relationships" cannot receive Holy Communion, according to the document.