A simple sugar pill may help treat a disease — even if patients know they’re getting fake medicine.

The finding, reported online Wednesday in the journal PloS One, may point the way to wider — and more ethical — applications of the well-known “placebo effect.”

“The conventional wisdom is you need to make a patient think they’re taking a drug, you have to use deception and lies,” said lead author Ted Kaptchuk, an associate professor of medicine at Harvard Medical School. And, Kaptchuk added, it seems many doctors do this: In one report, as many as half of rheumatologists and internists surveyed said they had intentionally given patients ineffective medication in the hopes it would have a positive result.

Kaptchuk, however, wondered whether the deception was needed. When he first tried to persuade fellow researchers to explore a sort of “honest” placebo, “they said it was nuts,” he said. After all, didn’t the whole effect hinge on people believing they were getting real treatment?

Patients were easier to enlist. “People said, ‘Wow, that’s weird’ and we said, ‘Yeah, we think it might work.'”

The researchers enrolled 80 people suffering from irritable bowel syndrome, explaining the experiment while framing it positively — they called it a novel “mind-body” therapy.

Half the patients were given a bottle with the word “placebo” printed on it. The pills it held, they were told, were like sugar pills. The patients were told they didn’t even need to believe in the placebo effect, but had to take the pills twice daily.

The other half were given no treatment at all.

At the end of the three-week trial, 59 percent of the patients taking the placebo said their symptoms had been adequately relieved, far outstripping the 35 percent in the non-treatment group.

“We were all taken aback,” Kaptchuk said. “We triple-checked the data before we decided it was real.”

Read the research paper at Plos One: Placebos without Deception: A Randomized Controlled Trial in Irritable Bowel Syndrome