Blood libels against Jews are false accusations that Jews use human blood in certain aspects of their religious rituals and holidays. In general, the libel alleged something like this: a child, normally a boy who had not yet reached puberty, was kidnapped or sometimes bought and taken to a hidden place (the house of a prominent member of the Jewish community, a synagogue, a cellar, etc.) where he would be kept hidden
until the time of his death.

The descriptions of torture and human sacrifice in the antisemitic blood libels run contrary to many of the teachings of Judaism. The Ten Commandments in the Torah forbid murder. In addition, the use of blood (human or otherwise) in cooking is prohibited by the kosher dietary laws. Blood from slaughtered animals may not be consumed, and must be drained out of the animal and covered with earth. (Lev 17:12-13) According to the book of Leviticus, blood from sacrificed animals may only be placed on the altar of the Great Temple in
Jerusalem (which no longer existed at the time of the Christian blood libels). Furthermore, consumption of human flesh violates kashrut.

While animal sacrifice was part of the practice of ancient Judaism, the Tanakh (Old Testament) and Jewish teaching portray human sacrifice as one of the evils that separated the pagans of Canaan from the Hebrews.(Deut 12:31, 2 Kings 16:3) Jews were prohibited from engaging in these rituals and were punished for doing so (Ex 34:15, Lev 20:2, Deut 18:12, Jer 7:31).