One popular notion of medicine is that a “magic bullet” — a cure for AIDS or cancer — awaits scientists in the chemistry of some undiscovered leaf in a remote rain forest.

That’s possible, but medicinal plants are far more likely to be weeds growing alongside a dirt road than exotic jungle plants.

UGA anthropology doctoral candidate John R. Stepp reached that conclusion in a seven-month study of the plant-gathering habits of the Maya in the Mexican state of Chiapas. He gathered his data in the same region of Chiapas that has seen broad media attention focused on another university research project, which, despite widespread support by Maya communities, has been suspended due to opposition of a group of Maya Indians who disputes the ownership of the native plants. Stepp’s findings were published in the March issue of Journal of Ethnopharmacology and were co-authored with Daniel E. Moerman, an anthropology professor at the University of Michigan-Dearborn.

“For a decade or so, people have pushed this notion of medicinal plants in the rain forest and the idea was the Indians would make a three-day trek to find them,” Stepp said. “Actually, what they do is simply walk outside the house and start looking around in nearby fields and vacant lots.

Because medicinal plants are so plentiful — and so easy to find — the Maya have developed a tremendous amount of practical pharmaceutical knowledge in the thousands of years they have lived in the region, he said.

“By the age of 5, a child can easily name 100 plants,” Stepp said. “An adult can name up to 600. The culture maintains this body of knowledge orally. And having this knowledge tends to diminish the need for shamans to treat common illness in that society. If you are sick, there’s no need to go to a specialized healer when you can find the cure yourself.”

Stepp conducted his study with 208 Maya living in small villages in a municipal district called Tenejapa. He interviewed his sources weekly, always asking what plants they had gathered and where they had found them.

He then compared the results to a database of the about 9,000 plants known to grow in Chiapas. Of those, 1,178 are classified as weeds — meaning they thrive in sunlight and tend to grow wild in disturbed areas, such as vacant lots, ditches, uncultivated fields and near abandoned buildings.

Had weeds been distributed randomly among the plants used by the Maya, there should have been about 13 species present. Instead, there were 35.

There may still be medicinal plants in the rain forest, Stepp said, but the medicines the Indians use are from more common plants.

“I’d hate to have this study be used as fodder for someone wanting to deforest an area,” he said. “What it does point out, however, is that a solely economic argument for conserving the rain forest is dangerous. The magic bullet could be in a vacant lot.”

For more information, e-mail rstepp@uga.edu.