The placebo effect is effective and improvement is the disease has been noted, even when patients have been informed that the pills they take aren't active medication.
The findings by the researchers at Harvard Medical School's Osher Research Center and Beth Israel Deaconess Medical Center (BIDMC) suggested that the placebo effect could work even without the deception.
Placebos are used in clinical trials as controls for potential new medications. Even though they contain no active ingredients, patients often respond to them.
Harvard Medical School associate professor of medicine Ted Kaptchuk and his colleagues at BIDMC wanted to explore whether the effect of placebos can be harnessed honestly and respectfully or not.
They conducted a three-week trial of 80 patients suffering from irritable bowel syndrome.
The patients were divided into two groups, with one group given no pills, and the other given pills honestly described as 'like sugar pills'. They were told to take the pills twice daily.
Nearly twice as many patients treated with the placebos reported adequate symptom relief (59 percent) compared with the group taking no pills (35 percent), according to the study.
The study claimed that patients taking the placebo doubled their rates of improvement to a degree roughly equivalent to the effects of the most powerful irritable bowel syndrome medications.
"Not only did we make it absolutely clear that these pills had no active ingredient and were made from inert substances, but we actually had 'placebo' printed on the bottle," said Kaptchuk.
"We told the patients that they didn't have to even believe in the placebo effect. Just take the pills," he added.
Although the study was limited in scope and would need to be confirmed by further research, Kaptchuk said the findings suggested there 'may be significant benefit to the very performance of medical ritual'.
"I'm excited about studying this further. Placebo may work even if patients knows it is a placebo," he added.
Senior study author Anthony Lembo of the Harvard Medical School said he was surprised with the results.
"I didn't think it would work. I felt awkward asking patients to literally take a placebo. But to my surprise, it seemed to work for many of them," he said.he study is published in the current issue of PLoS ONE.