Blood libel or ritual murder libel is an antisemitic canard which falsely accuses Jews of murdering Christians in order to use their blood in the performance of religious rituals. Echoing very old myths of secret cultic practices in many prehistoric societies, the claim, as it is leveled against Jews, was rarely attested to in antiquity. According to Tertullian, it originally emerged in late antiquity as an accusation made against members of the early Christian community of the Roman Empire. Once this accusation had been dismissed, it was revived a millennium later as a Christian slander against Jews in the medieval period. The first examples of medieval blood libel emerged in England in the mid 1100s before spreading into other parts of Europe, especially France and Germany. This libel, alongside those of well poisoning and host desecration, became a major theme of the persecution of Jews in Europe from that period down to modern times.

Antisemitic tropes or antisemitic canards are "sensational reports, misrepresentations, or fabrications" that are defamatory towards Judaism as a religion or defamatory towards Jews as an ethnic or religious group. Since as early as the 2nd century, libels or allegations of Jewish guilt and cruelty emerged as a recurring motif along with antisemitic conspiracy theories.