Actually nothing. In addition to the "frame". In the rite, identical threads appear in the same hierarchy. Above all, the believers of both churches believe in the same God. They use the same Bible.
Orthodox church of St. Nicholas in Bialystok (1846)
If you look for differences, it is worth paying attention to the fact that the Church is - in contrast to the Church - autocephalous. This means that each diocese is independent. The church has no head, no pope. In practice, this means that there is no - often mentioned in the media - the problem of reconciliation between Polish Orthodox and Catholics.
baptism by 3 times immersing in water
communion under two figures - bread and wine
a ban on honoring sculptures and granting indulgences
they do not recognize the purgatory, the Immaculate Conception and the Ascension of the Blessed Virgin Mary, the primacy of the Pope, the dogma of its infallibility
The Catholic church:
baptism through the glade of the head
communion under one form (bread)
at the head of the Church there is a pope who has power over all the faithful in the world; he is also the successor of Piotr
K.k acknowledges that the Holy Spirit comes from the Father and the Son
Team of the Archcathedral Basilica of the Assumption of the Blessed Virgin Mary in Bialystok - a temple complex in Bialystok, composed of two interconnected church buildings: the old (from the beginning of the 17th century) and the new (from the beginning of the 20th century).