That was encouraging, says Bal Lokeshwar. If it worked well at low doses, it was more likely to do its job without being toxic to humans.

Then they sought the mechanism by which BIRM was arresting the cancer. It turned out that, at low doses, it arrested the cancer's growth. At higher doses it killed the cancer cells, by de-fragmenting the DNA in them, causing them to almost literally explode.

For the in vivo part, the researchers used a dozen gray rats and injected cancerous cells from other rats' prostates just beneath their skin.

To the now-cancerous rats, they then applied BIRM -- one milliliter per rat, injected directly into the stomach -- the equivalent of about half a cup taken by mouth if it were a human patient.

The results were stunning: Half the injected rats never developed a tumor. In the rest, fewer tumors appeared than in the untreated rats in the study, and those that did appear grew more slowly.

And none of the rats showed any toxic effects.

In 2003 came a satisfying step for the researchers: publishing their work in the medical journal Cancer Chemotherapy and Pharmacologoy, and offering the conclusion that the treatment appears to work.

Still, the researchers didn't break out the champagne. "It's a routine thing, " Bal Lokeshwar says.

Then came drudgery: Applying for federal grants to continue their research. It was easy to demonstrate its importance. More American men contract prostate cancer than any other form of the disease, except skin cancer. The American Cancer Society says 218,890 new cases will be diagnosed in 2007, and 27,050 men will die of it.

And once prostate cancer has metastasized to other organs, chemotherapy struggles to slow it -- driving many patients to try alternative medicines.

Doctors know that developing effective, modern drugs from plants and even folk remedies is not unusual -- although perhaps pursued with more enthusiasm in Japan and China than in the United States.

The NIH liked the study, says Bal Lokeshwar. "But they had a million questions. What is BIRM? What plant is it based on? Is it grown in the wild? Cultivated? Who are the growers? Is it dried? Does it have pesticides? Funguses? Toxins? Is it reproducible?"

This was a problem. The researchers were in touch with Cevallos in Quito, had even bought BIRM from his U.S. distributor, Forest Life Corp., for testing -- at $120 a bottle. But the Ecuadoran doctor wasn't about to spill all of its secrets.

"We knew very little about it, " says Bal Lokeshwar. "We didn't know what was in it, whether it was a single ingredient or a compound. We didn't even know if the plant was cultivated or wild. It was a family secret. He was trying to patent it."

Cevallos was calling the plant Solanum dulcamara, and the Lokeshwars were using that name in their NIH application. But even when Bal Lokeshwar visited the Cevallos family in Quito in 2005 to speak before the Pan American Medical Association about his research with BIRM, he wasn't invited to see the plant.

"I can understand; it's their livelihood, " he says.

But the NIH demanded information. At that point Bal Lokeshwar's wife, UM researcher Vinata Lokeshwar, started negotiating.

The NIH wanted a sample of the plant identified and classified by a professional botanist. Luis Lopez, a researcher in Vinata's lab, found one, Dr. Hugo Navarrete, a botanist in Quito at the Pontifica Universidad Catolica del Ecuador.