Henry Knowles Beecher, a medical doctor and anaesthetist who served with the United States Army during the Second World War, is widely credited with popularising the modern concept of the placebo effect in medicine.
According to the story, while working at an army field hospital, Beecher faced a critical shortage of morphine for wounded soldiers in need of urgent pain relief. In desperation, he administered injections of saline (salt water) instead. To his astonishment, the soldiers responded as though they had received actual morphine. This remarkable observation sparked Beecher’s interest in the placebo effect and initiated decades of research into its extraordinary power.
The most extraordinary thing about this story, however, is that it probably never happened.
In 2015, the writer Shannon Harvey spent some time reading through Beecher’s published work and even contacted the library at Harvard, which holds his private archives. Harvey discovered that, while Beecher wrote extensively about the placebo effect, the story about running out of morphine does not appear in any of Beecher’s public or private writings. Nor does it appear in his 1976 obituary in the New York Times.
While Beecher wrote extensively about the placebo effect, the story about running out of morphine does not appear in any of Beecher’s public or private writings
Several years later, science communicator Jonathan Jarry and I tried tracing the origins of this tale. Jarry documented the numerous variations he encountered. In some versions, the events are set in North Africa; in others, they occur on a Pacific island or in Italy. Some accounts involve a nurse mistakenly administering saline, with the observant and guileful Beecher taking note. Others depict Beecher himself administering the saline. In one telling, Beecher even hands out cigarettes instead of salt water.
Curiously, the earliest version of the story we found wasn’t even about Henry Beecher. It appeared in a 1978 episode of the TV series M*A*S*H, in which wounded soldiers are given powdered sugar cribbed from the tops of doughnuts after a supply of morphine is accidentally contaminated and fresh stocks won’t arrive until morning.
When Jarry spoke with the writer of that episode, he learned that the plot had been provided by the series producer, Gene Reynolds. Where Reynolds got the idea from remains a mystery. He passed away in 2020.
The closest parallel we found in Beecher’s work comes from a 1946 paper, titled ‘Pain in Men Wounded in Battle’. In it, Beecher criticises the rote use of morphine on the battlefield and argues that other factors, such as anxiety, traumatic shock, or even simple thirst, are often the immediate cause of a wounded soldier’s distress. He recounts the case of a 19-year-old soldier who was severely injured and ‘wild with pain.’ The soldier was mistakenly given a sedative instead of morphine, which it turned out was sufficient to calm him down and allow him to sleep, without the need for pain relief. Beecher notes, ‘the dose [of sedative] given would not have controlled pain’ and concludes ‘his manic state was not due to pain.’
Regardless of whether the legend is true, Beecher played a pivotal role in highlighting the importance of the placebo effect in clinical research. This year marks the 70th anniversary of the publication of his landmark paper, ‘The Powerful Placebo,’ which found that 35% of patients in clinical trials improve after the administration of a placebo alone.
This appears to be the origin of the widely circulated medical truism that 30% of the effect of any drug is placebo, but these are fundamentally different claims. Saying that ‘30% of patients improve after a placebo’ is not the same as stating that ‘30% of a drug’s effect is attributable to placebo.’ This distinction is overlooked, and the latter interpretation has become the commonly cited version.
Beecher derived this statistic by examining fifteen studies which reported placebo effects, but the specifics of these studies raise questions about his methods and the legitimacy of this figure. For one thing, Beecher claims that the fifteen studies were ‘chosen at random’, but almost half of them were authored or co-authored by Beecher himself. This somewhat undermines the claim of random selection and suggests the possibility of a selection bias.
Also, none of the fifteen studies Beecher analysed were explicitly designed to investigate the placebo effect. Consequently, Beecher attributes all improvements in the control groups to the placebo effect, ignoring other possible explanations.
For example, in a 1933 study on the common cold, patients are reported as showing an improvement a couple of days after receiving a placebo, but six days after the onset of symptoms. Beecher attributes this improvement to the placebo effect, disregarding the fact that many colds will naturally improve within that timeframe — a fact even noted in the original paper! This failure to account for the natural course of an illness will have inflated the apparent placebo effect.
He also overlooks the influence of parallel interventions, where patients receive some additional treatment alongside the placebo that influences their outcomes. A patient who is coincidentally taking penicillin for an unrelated condition might see their improvement attributed to the placebo when the penicillin was actually responsible. Despite some studies explicitly mentioning such additional treatments, Beecher still credits all observed improvements to the placebo effect.
Another oversight was conditional switching of treatments. In this 1933 paper on angina, which is referenced in ‘The Powerful Placebo,’ patients in the placebo group were switched to the treatment group if their condition deteriorated. They were switched back to placebo once they were stable again. This practice exaggerates the apparent placebo effect, as patients are only permitted to remain in the placebo group for as long as they are improving.
In 1997, researchers Kienle & Kiene revisited the original fifteen papers cited in ‘The Powerful Placebo,’ and concluded that not a single one of them presented any compelling evidence for a real, therapeutic, placebo effect. They identified numerous unaddressed factors that could create the illusion of a placebo effect, including the natural progression of illness, parallel interventions, and conditional switching of treatment, as well as regression to the mean, observer bias, and answers of politeness. Perhaps the most damaging, however, is Beecher’s frequent misquoting of data. Reporting on a 1954 study on coughs by Gravenstein, Beecher claims that 36% of 22 patients showed an improvement with a placebo. However, Gravenstein does not have a placebo group of 22 patients, or any figure reported as 36%. Gravenstein even remarks that it was ‘not possible to answer the question’ of placebo effectiveness, as patients could not be studied without medication for any extended period.
This is not the only example of misquotation or even the most egregious. According to Kienle & Kiene, Beecher also ‘cited as a percentage of patients what in the original publications is referred to as something completely different, such as the number of pills given, the percentage of days treated, the amount of gas applied in an experimental setting, or the frequency of coughs after irritating a patient.’
Despite its reputation, nothing in ‘The Powerful Placebo’ demonstrates a convincing effect which could only be explained by a real, therapeutic placebo effect. Yet it remains one of, if not the, most cited paper in the placebo effect literature. This prompted Kienle & Kiene to comment that something about the placebo topic invites ‘sloppy methodological thinking.’
The same errors made by Beecher are still being made in the modern placebo effect literature. Correlation (the patient took a fake pill and improved) is mistaken for causation (the improvement was prompted by the fake pill.) Confounding effects like disease progression, parallel interventions, and regression to the mean are ignored.
Placebos have a crucial and perhaps irreplaceable role in medical research as a control, but that doesn’t mean they have a role in clinical care. After 70 years, perhaps it is past time we put the myth of the Powerful Placebo behind us.
