Can Catholic receive communion at a non-Catholic church?
If there is no Catholic Church in the area, a Catholic may receive the sacraments from an eastern Orthodox Church, such as in Russia. The Catholic Church recognizes the validity of Orthodox sacraments.
It does not recognize the sacraments of Protestant and so-called non-denominational churches, except Baptism and Matrimony. Catholics are NEVER allowed to receive their form of eucharist under any circumstances!
Fr. Vincent Serpa, O.P.