What were the gifts of the Magi really about?

That's not too difficult a question in this season of giving. Or is it?

Gold? Everybody knows why gold would be considered a generous gift with a new baby in the stable.

Frankincense? Not easy to spell, but it smells nice, making it an appropriate postpartum gift in a place full of mules and other beasts.

But myrrh? Just what is myrrh anyway? And why would someone give it to a baby?

As it turns out, myrrh, a bitter-tasting gum resin, might have been a very wise gift, if a late-20th-century analysis of the drugs of antiquity stands up. For one thing, it might have been useful for a new mom in the throes of postpartum pain and a male infant after circumcision.

Myrrh, studies reveal, was among the chief analgesics, or common painkillers, used in ancient times, particularly throughout the Middle East, Egypt and Ethiopia.

Scientists at the University of Florence in Italy have been studying myrrh for years, analyzing its chemical structure and teasing secrets from its molecular backbone, a configuration of tightly bound hydrocarbon rings.

As for where it comes from in the first place, myrrh is secreted by shrubs native to North Africa and the tropics that belong to the genus Commiphora, and is composed of essential oils, water-soluble gums and alcohol-soluble resins. (And just in case you're interested in even more botanical factoids, Commiphora belongs to the larger family of plants in the Burseraceae family, which are widely distributed around the globe. But more on that later.)

For the moment, it's back to the times of antiquity and all of the imaginative uses of myrrh.

Scientists at the University of Florence, intrigued by myrrh, looked into its ancient uses and found the Egyptians used it as an embalming fluid; the ancient Jews used myrrh as both anointing oil and painkiller. Hippocrates praised myrrh as a balm for sores; the Romans used it to treat mouth and eye infections, coughs and worm infestations.

In the Gospel of Mark, "vinum murratum," a mixture of wine and myrrh, was offered to Christ just before the Crucifixion. Given the analgesic effects of myrrh and the numbing effects of wine, it is perhaps safe to say the hope was that the concoction would provide a knockout dose of painkilling relief.

A closer look at the flowering plant family from which myrrh comes, though, reveals that Mother Nature probably had much in mind for a substance that ultimately would have metaphoric and medicinal value.

"Almost all of the Burseraceae family, if you cut into them, will exude a smell somewhat like turpentine," said Scott Mori, director of the Institute of Systematic Botany at the New York Botanical Garden.

"This is a very characteristic sort of thing," he said, "and if the plant is wounded, it will exude this slow-flowing exudate, or sap."

Nature's intentions for the sap, however, probably had more to do with an ever-escalating arms race between bugs and plants than with a biblical form of Tylenol. John D. Mitchell, honorary curator of the institute, said it's truly a jungle out there, especially in tropical realms where plants, such as those from which myrrh is drawn, routinely kill bugs. "When they take a bite, a resin squirts out," Mitchell said, which can prove to be a deadly meal.

Myrrh sap is highly toxic to bugs and is one way plants have of keeping bugs at bay. When bugs find ways around these various poisons, the plants, throughout evolutionary time, have countered by reconfiguring their molecules, making their compounds even more toxic than before.

Mori also points out that the group of plants in which myrrh is a member also is very closely related to the genus Boswellia, from which frankincense comes. And Boswellia, it turns out, also is in the Burseraceae family. True to its familial characteristics, frankincense also is a sap, and one the ancients likewise used for medicinal purposes, although they mostly enjoyed its perfume. Despite its more seductive odor, frankincense, too, is a potent bug killer, nature's pleasantly perfumy form of Black Flag.

Killer saps are common in tropical plants, Mori said. By contrast, frosty winters serve as the best insecticide against plant-eating bugs in more temperate zones because leaf-dormancy and frost-laden boughs are not the makings of a tasty dinner.

Studies in Florence suggest that chemicals in myrrh interact with the brain's opioid receptors, which probably explains why myrrh was used as a painkiller. But Italian scientists, led by pharmacist Piero Dolara, suggest that myrrh probably lost its attractiveness as an analgesic after more potent compounds, particularly opium, came into vogue.

Myrrh, these days, is sold as an incense and is used in perfumes.