He's doing it wrong
I was reading a really interesting article about birth-control through the ages over at DamnInteresting.com, and I came across this particular gem.
Ancient Rome's foremost gynecologist – a physician named Soranus – wrote that
women should drink the silphium juice with water once a month since "it not only
prevents conception but also destroys anything existing."
/me laughs venomously.
He's totally doing it wrong.