Generous but gullible people are sending millions of dollars to friends and strangers who are raising money for unproven, and even bogus, medical treatments, researchers said Tuesday.

They found more than 1,000 websites that had raised nearly $7 million for people who said they needed help getting homeopathy, stem cell treatments and other dubious cures.

“When we picked out five useless dangerous and quacklike interventions, we found they raised a tremendous amount of money to try and help desperate people to use them,” said Art Caplan, a bioethicist at New York University who worked on the study.

“There’s no doubt that there’s a lot of generosity out there, but there’s also no doubt that there are a lot of people willing to rip off the desperate.”

Dr. Ford Vox, a brain rehabilitation specialist at the Shepherd Center in Atlanta said he noticed just how many medical crowdfunding sites there were. He joined forces with the medical ethics team at NYU to see what people were giving money to.

“More than 1,000 medical crowdfunding campaigns for five treatments that are unsupported by evidence or potentially unsafe raised more than $6.7 million,” they wrote in a letter to the Journal of the American Medical Association. “Another study found that 408 campaigns raised more than $1 million for unproven stem cell interventions.”

They searched for people seeking cash for treatments known to be unproven or scientifically disproven. The searches included: homeopathy or naturopathy for cancer; hyperbaric oxygen therapy for brain injury; stem cell therapy for brain injury and spinal cord injury; and long-term antibiotic therapy for “chronic Lyme disease."

The Food and Drug Administration has issued public warnings against homeopathy and unproven stem cell therapies. Stem cell therapy is a broad term that covers both proven and unproven treatments, but clinics abound that offer “stem cell therapy” with no medical proof they work.

Although they checked a number of crowdfunding sites, GoFundMe had almost all the sketchy medical fundraisers, they found.

“The most money was raised by the 474 campaigns collecting funds for homeopathic or naturopathic cancer treatments at $3,464,871,” they wrote.

People were often seeking money to travel to overseas clinics, they found.

“We identified nine named practitioners and eight countries that campaigners intended to visit, including clinics in Germany and Mexico for homeopathic or naturopathic cancer treatments, a New Orleans clinic offering hyperbaric oxygen therapy for brain injury, and clinics in the United States, Panama, Thailand, India, China, and Mexico for stem cell therapies,” they wrote.

“Donors indirectly contributed millions of dollars to practitioners to deliver dubious, possibly unsafe care,” they added.

Caplan said he would like to see the sites police the fundraising campaigns they sponsor. People have no idea if the money they donate is really going to a legitimate cause, and medical supplications by definition pull at people’s heartstrings.

“If they raise money and they raise more than they need, where does it go? If they raise money and they don’t get enough, where does it go?” he asked. “Did their loved one die? Did they make it to Panama?”

GoFundMe said it tried to be open.

"We always encourage people to fully research whatever it is they are raising money for and to be absolutely transparent on their GoFundMe page, so donors can make an informed decision on what they’re donating to," the company said in a statement.

"That said, we have policies and processes in place to make sure we are the most trusted social fundraising platform. We have a set of terms and conditions and will remove any campaign that violates our terms of service."

Caplan has harsh words for the clinics that offer the bogus treatments that the desperately ill fall for.

“The clinics promise them cures. They promise hope when there really isn’t any,” Caplan said.