Plant-Derived Birth Control Is Ancient History

Biology: Historical information shows that birth control may have been derived from plants as far back as the ancient Greeks. Though some are skeptical about the plants' effectiveness, others believe the practices may have had a significant impact on society.

After they have sex, some of the Appalachian women of Virginia and North Carolina take a teaspoonful of seeds from the common weed called Queen Anne's lace, crush them, stir them into a glass of water and drink the gritty preparation. They say it keeps them from getting pregnant.

As it happens, the same plant grows in rural parts of India's Rajasthan state, and peasant women there chew and swallow the seeds dry. They, too, rely on it as a form of contraception.

Though a world apart today, women in both regions possess knowledge that can be traced back at least 2,500 years - to ancient Greek physicians, including Hippocrates, who prescribed seeds of Queen Anne's lace as both a contraceptive and as an herbal "morning-after pill."

In fact, according to John Riddle, a historian of medicine at North Carolina State University in Raleigh, who unearthed the tradition, evidence is accumulating not only that the venerable methods do work in animal tests, but that the knowledge, use and social acceptance of effective, plant-derived birth-control drugs was widespread in the ancient world. Riddle recently published his findings in a book, "Contraception and Abortion from the Ancient World to the Renaissance."

According to Riddle, herbal birth control created much of the wealth of the Greek city-state of Cyrene on the coast of what is now Libya. Cyrenians collected and exported the sap of a plant that the Greeks called silphion and the Romans, silphium. An image of the plant appears on 5th century B.C. Cyrenian coins.

The Roman naturalist, Pliny the Elder, mentions that silphion cost more than its weight in silver. So well-known was silphion that Aristophanes discusses its cost in one of his plays.

Why was the plant so valued? According to the ancient physician Soranus, "Cyreniac juice," as he called it, when taken by mouth, would prevent conception or induce an abortion.

By the 4th century A.D., however, silphium died out, apparently harvested to extinction. Women seeking an alternative turned to silphion's close relatives in the giant-fennel family, including asafoetida, a key ingredient in today's Worcestershire sauce. Though said to be less effective than silphium, asafoetida was cheaper and widely prescribed in the ancient world.

Riddle said ancient documents name many other plants used to regulate fertility. Among the more prominent are pennyroyal, rue, willow, date palm, pomegranate, members of the genus Artemisia (such as wormwood) and myrrh.

Such concoctions have usually been dismissed by modern medical experts as ineffectual, but tests on laboratory animals in recent years have proved otherwise.

Although silphium can never be tested scientifically, experiments using crude extracts of asafoetida show that it does something. In rats, for example, it inhibited implantation of fertilized ova at rates up to 50 percent. Extracts of asafoetida's close relatives were nearly 100 percent effective in preventing pregnancy when given within three days of mating.

According to Norman Farnsworth, a pharmacologist at the University of Illinois-Chicago who has collected the evidence for years, experiments on animals show that some 450 plant species worldwide contain natural substances that prevent ovulation, block fertilization, stop implantation or reduce fertility in some other way.

Many plants contain estrogen-like compounds that alter the subtle balance of hormones needed for conception and maintenance of pregnancy. Some have substances that simply make the Fallopian tube transport the egg so fast that it enters the uterus before it can be fertilized and dies because it cannot survive there in that state. One plant, Farnsworth said, simply inhibits an enzyme that the sperm must release to penetrate the egg.

Even foods in an ordinary diet can have contraceptive effects, Farnsworth found - peas, for example. The clue emerged from the fact that in the history of Tibet the population has been stable for periods of up to 200 years. During those times Tibetans subsisted largely on barley and peas. When mice were fed a diet of 20 percent peas, litter sizes dropped in half. At 30 percent peas, the mice failed to reproduce at all.