According to a survey of doctors in the United Kingdom, 97 percent have prescribed a placebo treatment to patients at least once in their career.
Most doctors admitted to prescribing what are known as "impure" placebos-treatments that are unproven or unnecessary, such as prescribing an antibiotic treatment for a viral infection on conducting blood tests or non-essential physical examinations in order to reassure patients-at least once.
Only 12 percent of UK doctors admitted to ever using a "pure" placebo, such as sugar pills or saline injections, which contain no medicine or active ingredients.
"This is not about doctors deceiving patients," said Dr. Jeremy Howick, co-lead author of the study from the University of Oxford. "The study shows that placebo use is widespread in the UK, and doctors clearly believe that placebos can help patients."
The survey, taken by 783 a representative sampling of primary care practitioners in the UK, assessed the physicians' beliefs of ethical acceptability of placebo use.
A majority of physicians believed placebo use was wan acceptable practice, with 66 percent of those surveyed saying they agreed it was sometimes acceptable to use a pure placebo and 84 percent saying it was acceptable to use an impure placebo.
Thirty-three percent of physicians surveyed said administering a pure placebo never acceptable.
More than 90 percent of physicians objected to placebo use in circumstances where use would endanger patient doctor trust and 82 percent of those surveyed said it was unacceptable to deceptively administer a placebo.
The widespread use and acceptance of placebos is consistent with other surveys of doctors around the world, but placebo use is currently against General Medical Council ethical codes. "Current ethical rulings on placebos ought to be revisited in light of the strong evidence suggesting that doctors broadly support their use," said Dr Howick.
"This latest study with the University of Oxford demonstrates that doctors are generally using placebos in good faith to help patients," said professor George Lewith, co-lead author of the study from the University of Southampton.
"Other previous published studies by Southampton have clearly shown placebos can help many people and can be effective for a long time after administration. The placebo effect works by releasing our body's own natural painkillers into our nervous system. In my opinion the stigma attached to placebo use is irrational, and further investigation is needed to develop ethical, cost-effective placebos."
The study is published in the open-access journal PLOS ONE.