The plague cure, Levaquin, was approved by the US Food and Drug Administration (FDA) this week.
The approval comes amid fears that the ancient illness that ravaged Europe in the 14th century could be used in a bioterror attack.
The plague is extremely rare in modern times, with about 1,000 to 2,000 cases each year.
Yet, during the middle ages, the plague or "black death," is said to have killed 30 to 60 percent of Europe's population.
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The new antibiotic, generically known as levofloxacin, is used to both prevent the disease from occuring in people exposed to it and to treat those already suffering.
AFP reported that the drug was approved after trials on monkeys.
Yet no human studies were done as there are not enough cases of plague in humans to conduct a clinical trial.
Several tetracycline drugs are currently prescribed for the plague.
“Today’s approval broadens the available therapeutic treatments for plague,” says Edward Cox, an FDA researchers said in a statement.
“It also further demonstrates the usefulness of animal model studies to collect needed efficacy data in cases where human trials are not ethical or feasible.”