WORKING WITH the Highland Maya in Chiapas, Mexico, University of Georgia researcher John R. Stepp has documented that weeds are a more valuable source of medicine than plants found deep in the forest. Stepp spent 9 months tracking medicinal plant use of 208 people in 6 communities. He found that the majority of medicines used were made from weeds found close by homes and villages.
The Maya are well known for their use of medicinal plants, and in recent years scientists from around the world have tapped into their knowledge in search of cures for cancer, AIDS, and other devastating diseases. But very little research has been done on the medicinal value of weeds — those pesky invasive species that quickly take over disturbed habitat near homes and other cleared areas. According to Stepp, weeds are a logical choice for medicinal use, “Weeds are readily available. You know that they are going to be there when you go looking for them. If you’re sick, you don’t want to travel a long ways to find a plant.”
Using weeds found close to home eliminates the need to store plants, saving time and effort. “Some of the more volatile compounds, if you dry them, lose their strength. So it’s much better from a treatment point of view to go out and get fresh material,” Stepp says. In contrast to other Indian groups throughout Latin America who dry and store plants, the Highland Maya rely almost exclusively on fresh material.
There are biochemical reasons why weeds make good medicine as well. Most plants manufacture compounds for defense against herbivores and insects. A lot of these compounds have medicinal properties — in small doses they are medicinal, in large doses they are toxic. Weeds tend to produce more compounds than plants living in the forest, who use structural defenses like thick bark and tannins to protect against browsing. Because most weeds only live for a short period of time, they can’t afford to expend the energy required to develop structural defenses. Developing chemical defenses is much more economical.
Stepp found that the majority of medicinal weeds were used for gastrointestinal diseases and respiratory illnesses, two conditions that account for 80% of health problems. One of the most frequently used weeds is the species Verbena litoralis. Named Yakan kulub wamal in Maya (grasshopper leg herb), this weed provides a potent cure for diarrhea. The Mexican sunflower, Tithonia diversifolia, is used to treat abdominal pain and diarrhea.
The Highland Maya have lived in the Chiapas region of Mexico for more than one thousand years. As a result, they have accumulated a vast understanding of medicinal flora that has been passed down through oral traditions to today’s population of 800,000 people. By the age of 5, children can name 100 plants, and adults can name nearly 600. This widespread knowledge has minimized the need for specialized healers. Unless they have a very serious illness or a condition with a supernatural element — like a curse — most people simply go out in the backyard and treat themselves.
Stepp says his study contrasts with the romantic image of native people gathering secret plants deep in the rainforest. “The truth is more exotic,” he explains. “I think the fact that people do have such a widespread knowledge and that they’re living on top of their pharmacy is more exotic than trekking off into the jungle.”
Published in Americas Magazine by Chris Hardman