A survey of UK doctors found that 97% have prescribed placebo treatments to patients at least once in their career. Researchers at the Universities of Oxford and Southampton in the UK discovered that 97% of doctors have used 'impure' placebo treatments, while 12% have used 'pure' placebos.

'Impure' placebos are treatments that are unproven, such as antibiotics for suspected viral infections, or more commonly non-essential physical examinations and blood tests performed to reassure patients. 'Pure' placebos are treatments such as sugar pills or saline（盐水） injections which contain no active ingredients.

A random sample of doctors was surveyed online, and returned 783 responses. This sample was found to be representative of all UK doctors registered with the General Medical Council (GMC). The research was funded by the National Institute for Health Research, the University of Oxford Department of Primary Health Care Sciences and The Southampton Complementary Medical Research Trust. The results are published in the open-access journal PLOS ONE.

'This is not about doctors deceiving patients,' says 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 showed that doctors prescribing both pure and impure placebos reported doing so for broadly similar reasons. Placebos were mainly given to either induce psychological treatment effects, because patients requested treatment or to reassure patients.

Ethical attitudes towards placebo usage varied among doctors, with 66% saying that pure placebos are ethically acceptable under certain circumstances and 33% saying they are never acceptable. Impure placebos were more widely accepted, with 84% of doctors deeming them acceptable.

This widespread use and acceptance of placebos is consistent with similar studies worldwide, yet they are still 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,' says Dr Howick.

For both pure and impure placebos, over 90% of doctors objected to their use where it endangered patient/doctor trust and over 80% were against using them if it involved deception（欺骗）.

'This latest study with the University of Oxford demonstrates that doctors are generally using placebos in good faith to help patients,' says 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.'