“We now have evidence to suggest that using alternative medicine in place of proven cancer therapies results in worse survival,” lead researcher Skyler Johnson told the Yale News.

The researchers looked at 10 years’ worth of records from the National Cancer Database and found that 281 patients within that time who had early-stage breast, lung, prostate or colorectal cancer who decided to take an alternative approach to their treatment. Those patients were then compared to 560 others with the same diagnoses who chose more scientific approaches like chemotherapy, surgery and radiation.

Feeling bad about being down can make things worse, says study

Patients who chose alternative medicine approaches that include things like “herbs, botanicals, homeopathy, special diets or energy crystals — which are basically just stones that people believe to have healing powers,” Dr. Johnson told New Scientist, were two and a half times more likely than their modern medicine-opting counterparts to die within five years.

To account for disparities that people face in the medical world (such as not being able to afford expensive chemotherapy treatments) the researchers placed biases in favor of the alternative medicine group — they were all younger, more affluent and were otherwise healthy.

“These patients should be doing better than the standard therapy group, but they’re not,” researcher James Yu told MedPage Today. “That’s a scary thing to me. These are young patients who could potentially be cured, and they’re being sold snake oil by unscrupulous alternative medicine practitioners.”

With this data and the urging of oncologists and all of their cancer expertise, the researchers are hopeful that doctors can educate their patients and communicate to them all of the drastic risks of alternative medical approaches.

“Because of patient autonomy, they can do whatever they want,” Yu said. “We’re always advising them (but) we can’t make them do anything.”