More than 200 million medication errors are made in the NHS every year that could lead to thousands of deaths, researchers say.
Mistakes - 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 study, commissioned by the Department of Health and Social Care, said the estimated 237 million errors could be costing the NHS £1.6 billion every year.
Health and Social Care Secretary Jeremy Hunt said the research showed medication error is "a far bigger problem than generally recognised" and causing "totally preventable" harm and deaths.
Researchers from the Universities of York, Manchester and Sheffield collated the amount of "preventable errors" in prescribing, dispensing, administering and monitoring medication.
The report said errors may cause inappropriate medication use or patient harm.
Mr Hunt will announce new measures to improve patient safety and reduce harm when he addresses the Global Patient Safety summit on Friday.
Mr Hunt will say: "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 which the Department of Health and Social Care said could reduce errors by 50%.
Pharmacists will also be given 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".
Dr Andrew Iddles, whose 102-year-old mother was given medication intended for the patient in the next bed, said: "My mother was given medication intended for another patient - a genuine mistake but it could have had fatal consequences.
"Whilst we were lucky that the error was recognised and reported, it is encouraging to see the NHS taking positive action to tackle these potentially devastating errors - above all, transparency is essential so staff can admit to mistakes early without being afraid of losing their job."