The Canons of the Council in Trullo; Often Called The Quinisext Council 11Canon XI.

Let no one in the priestly order nor any layman eat the unleavened bread of the Jews, nor have any familiar intercourse with them, nor summon them in illness, nor receive medicines from them, nor bathe with them; but if anyone shall take in hand to do so, if he is a cleric, let him be deposed, but if a layman let him be cut off.