Many medical uses were ascribed to the plant. It was said that it could be used to treat cough, sore throat, fever, indigestion, aches and pains, warts, and all kinds of maladies. Chiefly among its medical uses, according to Pliny the Elder, was its role as a herbal contraceptive. Given that many species in the parsley family have estrogenic properties, and some (such as Queen Anne's lace) have been found to work as an abortifacient, it is quite possible that this particular use may well have had merit.
The plant grew along a narrow area, about 125 by 35 miles in Cyrenaica in what is present-day Libya. Legend said that it was a gift from the god Apollo. Used widely by most ancient Mediterranean cultures, the Romans considered it "worth its weight in denarii." Speculation abounds as to the cause of its extinction; much of it rests on a sudden demand for the meat of animals who had grazed on the plant, for some supposed effect on its quality. Overgrazing combined with overharvesting likely led to its extinction.
There has been some speculation about the connection between silphium and the traditional heart shape. The Catholic Church claims that the symbol of the heart began in the 1600s when Saint Margaret Mary Alacoque had a vision of a heart shape inside a crown of thorns. However, the symbol is present in stained glass works from far earlier than that. The symbol is remarkably similar to the Egyptian "heart soul" (ab). The sexual nature of that concept, combined with the widespread use of silphium in ancient Egypt for birth control, and the fact that the seeds of silphium are shaped like a heart, leads to speculation that the character for ab may have been derived from the shape of the silphium seed.