Researchers have long been captivated by the phenomenon’s seeming potential in treating a range of ailments. In studies, they argue that placebos have notable, if poorly understood, healing effects even when patients are fully aware that they are taking inert pills. In surveys, doctors report wide use of placebos, especially for patients with complex conditions that have no clear treatment.

But in a recent paper in the Medical Journal of Australia, Dr. Maher argues that the medical community has become enthralled with the idea of “enshrining placebos as mysterious and highly effective,” even with little evidence of their efficacy in clinical care.

Much of the research, Dr. Maher says, has significant flaws that inflate placebos’ strength and reliability as therapeutics. These errors, he says, risk further entrenching the clinical use of placebos when proven treatments remain available, and encouraging entrepreneurs who are trying to cash in on online sales of placebo pills.

“The idea that we can use placebos as a panacea for a range of health conditions is really problematic,” he said. “It is bad for science and bad for patients.”