Doctors and nurses are left "terrified" that if they are open about their mistakes they could be struck off the medical register, Health and Social Care Secretary Jeremy Hunt has warned, after it emerged that more than 200 million medication errors are made by the NHS every year.
Mistakes, ranging from giving patients the wrong medication to delivering prescriptions late, may cause around 1,700 deaths annually in England and contribute to up to 22,000 each year, the new research has found.
According to the study, commissioned by the Department of Health and Social Care, the errors could be costing the NHS £1.6 billion every year.
Mr Hunt said any clinician wants to be completely open and transparent about mistakes they have made but are often left in fear of the consequences.
"In modern healthcare systems we make that practically impossible," he said.
"People are terrified that if they're open about what happens, they will be removed from the register, they might get fired by their hospital, it'll be bad for the reputation of their unit, the reputation of their trust.
"A thousand worries prevent the one thing that really should be happening, which is proper learning from that mistake, and then a proper attempt to make sure it can never be repeated."
Speaking as he delivered a keynote speech at the World Patient Safety Summit in London, Mr Hunt said the research on medication errors show it is "a far bigger problem than generally recognised" and causing "totally preventable" harm and deaths.
Researchers from the Universities of York, Manchester and Sheffield estimate around 237 million medication errors are made in England annually.
These can occur at any point a patient comes into contact with a drug, from prescribing, dispensing, administering to monitoring, and are defined as preventable errors which may cause inappropriate medication use or patient harm.
Announcing new measures to improve patient safety and reduce harm, he added: "This new study shows medication error in the NHS and globally is a far bigger problem than generally recognised, causing appalling levels of harm and death that are totally preventable.
"We are taking a number of steps today, but part of the change needs also to be cultural: moving from a blame culture to a learning culture so doctors and nurses are supported to be open about mistakes rather than cover them up for fear of losing their job."
Planned changes include introducing electronic prescribing systems across more NHS hospitals this year, which could reduce errors by 50%.
Pharmacists will also be given new defences if they make accidental errors, rather than being prosecuted, to ensure the NHS learns from mistakes and "builds a culture of openness and transparency".
But Janet Davies, chief executive of the Royal College of Nursing, said many mistakes could be prevented by better staffing levels.
"Short staffing and severe financial pressures create an environment where it's easier to make mistakes," she said.
"Our members tell us they are rushed off their feet and are being moved from ward to ward because there aren't enough staff. The high use of agency nurses brings an unintended risk too, fewer mistakes are made when patients are cared for by staff who work permanently at that hospital and know its patients, equipment and procedures."