by Andrew Downie

NINACACA, Peru — High in the Peruvian Andes, a shaman rubs a fluffy white rabbit all over Chris Kilham’s body, murmuring in Quechua, the language of these barren plains. Then she slits the animal’s throat and lets the blood run into a tiny grave.

To Mr. Kilham, the offering — an appeal to the gods for a bountiful harvest of maca, a local tuber — is just another day at the office.

Part David Attenborough, part Indiana Jones, Mr. Kilham, an ethnobotanist from Massachusetts who calls himself the Medicine Hunter, has scoured remote jungles and highlands for three decades for plants, oils and extracts that can heal. He has eaten bees and scorpions in China, fired blow guns with Amazonian natives, and learned traditional war dances from Pacific Islanders.

But behind the colorful tales lies the prospect of money, lots of money — for Western pharmaceutical companies, impoverished indigenous tribes and Mr. Kilham.

Products that once seemed exotic, like ginseng, ginkgo biloba or aloe vera, now roll off the tongues of Westerners. All told, natural plant substances generate more than $75 billion in sales each year for the pharmaceutical industry, $20 billion in herbal supplement sales, and around $3 billion in cosmetics sales, according to a study by the European Commission.

Although the efficacy of some of the products the herbal ingredients go into is hotly debated, their popularity is not in doubt. Thirty-six percent of adults in the United States use some form of what experts call complementary and alternative medicine, CAM for short, according to a 2004 study published by the National Center for Complementary and Alternative Medicine, a division of the National Institutes of Health.

Mr. Kilham believes multinational drug companies underutilize the medicinal properties in plants. They pack pills with artificial compounds and sell them at huge markups, he says. He wants Westerners to use the pure plant medicines that indigenous peoples have used for thousands of years.

“People in the U.S. are more cranked up on pharmaceutical drugs than any other culture in the world today,” Mr. Kilham said. “I want people using safer medicine. And that means plant medicine.”

Easy going and earnest, Mr. Kilham, 55, caught the plant bug after taking an herb walk at an organic farm in Natick, Mass., in 1971. A self-described hippie, he was already into “yoga, natural foods and meditation” and the discovery that plants had medicinal properties had a profound effect. He created a course in holistic health at the University of Massachusetts at Amherst, where he is now on the faculty, and made his first overseas trip — to India — to track down exotic flora.

Now he can identify unusual plants by their Latin names and he proudly regales the uninitiated on their individual properties. Shortly after leaving Lima on a trip taking French businessmen to the Peruvian Andes, he stopped the van and enthusiastically explained how the tropane alkaloids in a dusty plant he spotted by the side of the road are used by ophthalmologists to dilate pupils for eye examinations.

Such properties are often well known by indigenous peoples. So-called bioprospectors can make their fortunes by bringing those advantages to the attention of companies who identify the plant’s active compound and use it as a base ingredient for new products that they patent.

Some 62 percent of all cancer drugs approved by the Food and Drug Administration come from such discoveries, according to a study by the United Nations University, a scholarly institution affiliated with the United Nations.

“Latin American nations, especially Amazonian nations, have extremely rich and diverse flora, so the potential for commercial applications appears great,” said Tony Gross, a Brazil-based researcher at the university. “They say that in one in 10,000 you get something interesting. So it is not a gold mine, but when you do hit on something that does become a market leader you can make enormous amounts of money from it.”

In Peru, Mr. Kilham is betting on maca, a small root vegetable that grows here in the central highlands — “a turnip that packs a punch,” he says, adding “it imparts energy, sex drive and stamina like nothing else.”

That view is supported by studies carried out at the International Potato Center, a Lima-based research center that is internationally financed and staffed. Studies there show maca improves stamina, reduces the risk of prostate cancer and increases the motility, volume and quality of sperm.

Some peer reviewed studies published in the journal Reproductive Biology and Endocrinology backed up those findings.

For centuries, maca has been a revered crop in this austerely beautiful region 155 miles northeast of Lima. Inca warriors ate it before going into battle. Later, Peruvians used it to pay taxes to Spanish conquistadors.

Today, locals consume it boiled alongside dried vicuña meat in soups; or diced with carrots, peas and cauliflowers in salads. Maca flour is used to make sponge cake. Flavored with chocolate, it is made into maca puffs. Villagers offer visitors maca drinks and maca juice; airports sell maca toffees.

Mr. Kilham first heard about the tuber in 1996. Two years later, he went to Peru to find out more. There he formed a partnership with Sergio Cam, a Peruvian entrepreneur who invested much of the money he made as a construction worker in California from 1984 to 1999 to start Chakarunas Trading. The company is named after the Quechua word for men who build bridges between cultures.

Today, Chakarunas organizes local growers to sell their maca to the French firm Naturex, which extracts it into concentrate. Naturex sells the concentrate to Enzymatic Therapy, a Wisconsin-based company that makes and markets the finished maca products.

Thanks to the health supplements boom, both companies have grown, with Naturex’s revenues topping $125 million in 2007 and Enzymatic Therapy’s surpassing $80 million. Enzymatic Therapy sells $200,000 worth of maca-based products each month, said the company’s chief executive Randy Rose.

One product, Maca Stimulant, is sold in Wal-Mart under Mr. Kilham’s Medicine Hunter brand. Mr. Kilham earns a retainer from both Naturex and Enzymatic Therapy, in addition to royalties from another Medicine Hunter-branded product at Wal-Mart.

Mr. Kilham says he earns around $200,000 each year in retainers, and sales are so buoyant he expects to make “in the mid-six figures” in royalties next year.

Mr. Kilham insists he is not in the business simply for financial gain. His motivation comes from promoting herbal medicines and helping traditional communities, he said.

“I have financial security and don’t need to make money from this,” he said. “I believe trade is the best way to get good medicines to the public, to help the environment and to help indigenous people.”

He and Mr. Cam pay growers here in Ninacaca a premium of 6 soles (about $2) for a kilo of maca, almost twice the going rate of 3 to 3.40 soles a kilo. They have set up a computer room at the Chakarunas warehouse and a free dental clinic, the town’s first.

Mr. Kilham is clearly adored by the locals in these desolate, wind-swept villages. On a recent visit here, shamans, maca growers and their families flocked to him. Since only maca and potatoes grow at this altitude, they are thankful Mr. Kilham is helping them sell their produce.

He makes a point of returning regularly to Peru to affirm his commitment to the project. On this trip, his third this year, he brought executives from Phythea, a French company that sold 40 million euros of natural products last year. Phythea’s president, Laurent Mallet, had heard about maca and wanted to see both the agricultural and social aspect of Chakarunas Trading up close.

Mr. Mallet said he was so touched by the people and the rawness of their surroundings — it took him seven hours by van to get here, and several doses of oxygen to offset the headaches and nausea brought on by the altitude — that he vowed to increase his order of maca from five to 25 tons next year, if clinical trials in Bordeaux confirmed that maca reduces hot flashes and night sweats in menopausal women.

“I think it could be a very good product for us,” Mr. Mallet said. “I especially like the human dimension. They want to build a school and a medical center.”

To be sure, not everyone is so positive. Mr. Kilham runs the constant risk of being branded a “biopirate,” an outsider who steals traditional knowledge and fails to pass on the benefits to the local community.

In 2001, the company Mr. Kilham worked for at the time, Pure World Botanics, obtained United States patents for isolating and extracting maca’s key active compounds. The Peruvian government accused the company of profiting from what was rightfully Peru’s.

Mr. Kilham said he fought to make his bosses open up the patents. The company denied they had acted improperly but Naturex, which bought Pure World Botanics in 2005, granted Peruvian companies free licenses to the patents and vowed to increase the price paid per kilo to maca farmers by 15 percent.

“At Naturex,” the company’s marketing manager, Antoine Dauby, said in a statement, “we believe in giving back to the communities where we do business. And we’re doing that in Peru.”