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Digestive Diseases News Summer 2011

Placebos Effectively Treat IBS Symptoms

Photo of white, round pills poured out on a surface next to a partial view of an open pill bottle lying on its side.

Anumber of studies have shown improvements in irritable bowel syndrome (IBS) symptoms in response to placebo treatments. According to a recent study funded in part by the National Institutes of Health’s National Center for Complementary and Alternative Medicine (NCCAM), placebos improved symptoms of IBS, even when study participants knew they were taking placebos—essentially sugar pills with no active ingredient.

IBS is characterized by abdominal pain, bloating, constipation, and diarrhea. The disorder causes gastrointestinal (GI) discomfort and distress but is not linked to other GI problems, such as cancer and inflammatory bowel disease.

In the past, scientists had generally attributed beneficial responses to placebos to the fact that patients did not know if they were receiving a placebo or an active treatment. Despite the recognition of possible benefit, the use of a placebo without a patient’s knowledge poses an ethical problem for most clinicians. The new study examined the use of a placebo pill, given with the patients’ knowledge, compared with no treatment in relieving symptoms of IBS.

Researchers followed 80 adults with IBS for 3 weeks. Participants were randomly assigned to receive either placebo pills or no treatment. The participants in the placebo group were informed that “placebo pills, made of an inert substance, like sugar pills, have been shown in clinical studies to produce significant improvement in IBS symptoms through mind-body healing processes.”

The researchers assessed the participants at the midpoint and at the end of the study with a brief physical examination and patient questionnaires that measured symptom improvement. The researchers found that the participants in the placebo group had significantly better scores in global improvement, severity of symptoms, and adequate relief than the no-treatment group at both the midpoint and the end of the study. In addition, the placebo group had a trend toward improvement in quality of life.

Based on these findings, the researchers suggested that placebo treatments, when administered without concealment and with a plausible rationale of their potential effects, may produce beneficial responses in patients.

“Further research is warranted in IBS and perhaps other illnesses to confirm that placebo treatments can be beneficial when provided openly and to determine the best methods for administering such treatments,” wrote Ted J. Kaptchuk, O.M.D., associate professor of medicine, Beth Israel Deaconess Medical Center, and co-authors in their report, which appeared in the December 2010 issue of PLoS One.

For more information about complementary and alternative medicine, visit the NCCAM website at

For more information about clinical trials involving the use of placebos to treat IBS, search for NCT01010191 at

The National Digestive Diseases Information Clearinghouse, an information service of the National Institute of Diabetes and Digestive and Kidney Diseases, has free fact sheets and easy-to-read booklets about IBS. For more information or to obtain copies, visit

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NIH Publication No. 11–4552
September 2011

The National Digestive Diseases Information Clearinghouse is a service of the National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health.

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