In saying her critics ''manufactured a blood libel'', Sarah Palin used a phrase linked to the false accusations made for centuries against Jews, often to malign them as child murderers who coveted the blood of Christian children.

Blood libel has been a central fable of anti-Semitism in which Jews have been accused of using the blood of Gentile children for medicinal purposes or to mix in with matzo, or unleavened bread traditionally eaten at Passover.

The spread of blood libel dates to the Middle Ages - and perhaps further back - and those lies have led to massacres of Jews.

The term carries particular power among Jews, though it has taken on other meanings.

Abraham Foxman, the national director of the US Anti-Defamation League, said that while the term had become part of ''English parlance to refer to someone being falsely accused, we wish that Palin had used another phrase, instead of one so fraught with pain in Jewish history''.

One of the first recorded tragedies attributed to blood libel occurred in the 12th century, when a boy named William in Norwich, England, was found dead with stab wounds. Jews were accused of killing him in ritual fashion and several sources say most of the Jewish population was wiped out in a massacre.

Allegations of blood libel spread during the Holocaust.

Sarah Palin cops flak for term offensive to Jewish people