The inappropriate prescription of a drug to treat indigestion is reported to be costing the NHS £100m a year.
Researchers have warned that a quarter of the spending on proton pump inhibitors (PPIs), is unnecessary.
In addition, the drugs can have serious side effects when they are wrongly used, such as osteoporosis, kidney problems, pneumonia, and infection with hospital superbug C. difficile.
A report in the British Medical Journal found that between half and two-thirds of the prescriptions of the drug were "inappropriate" and flouted NHS guidelines against using powerful drugs to treat minor ailments.
The drugs can be used to effectively prevent heartburn and treat ulcers by stopping the backflow of stomach acid. However, the report found that in many cases other cheaper medications can be used to treat indigestion.
Last year in the UK, 36 million prescriptions were written for PPIs; triple the amount in 2000. Dr Mitchell Katz, of the San Francisco Department of Public Health, said this was a major problem in a piece in the Archives of Internal Medicine.
"That PPIs relieve dyspepsia is without question but at what cost – and I do not mean financial," he said.