The vial costs less than a cup of coffee. It has sat on hospital shelves for more than thirty years, used routinely in heart operations and a handful of joint replacements, trusted by the surgeons who reach for it and quietly ignored by everyone else. Tranexamic acid is not new, not patented, not exciting. And it now appears to be one of the most consequential drugs that most major surgeries have never bothered to use.

That, at least, is the upshot of a sprawling Canadian trial published this week in the New England Journal of Medicine. The headline number is plain enough: patients given the drug during major surgery needed fewer blood transfusions, and they did so without paying the price doctors had long feared.

That fear is worth dwelling on, because it explains the puzzle. Tranexamic acid works by stabilizing clots, stopping the body from dissolving them too quickly, which is exactly what you want when a patient is bleeding on the table. But a drug that props up clotting carries an obvious worry. What if those clots form where they shouldn’t, lodging in a leg vein or travelling to the lungs? For cancer surgery in particular, where patients already run a higher clotting risk, that question had kept the drug more or less off-limits.

So the team set out to answer it properly. Not with a small study, but with something closer to a real-world experiment across an entire hospital system.

The design they landed on is rather clever. Rather than randomizing individual patients, the researchers randomized whole hospitals, switching each one between a blanket policy of tranexamic acid and a placebo every four weeks, back and forth, for roughly two years. Ten Canadian hospitals took part. By the end they had data on 8,273 major operations performed between February 2022 and March 2024, drawn straight from clinical and administrative records.

“This is transformative to patient care and globally has the potential to save millions of units of red blood cells each year,” says Brett Houston, a hematologist and clinician-scientist at the University of Manitoba and CancerCare Manitoba, and one of the study’s lead authors.

The Number That Mattered Most

Here is what they found. Among patients who got the drug, 7.4 per cent needed a red-cell transfusion during their hospital stay, against 9.8 per cent in the placebo group. That works out at roughly ten units of blood saved for every hundred patients treated, a quietly enormous figure once you scale it across a health system. And the clotting? The thing everyone had worried about? Venous blood clots within 90 days turned up in 2.1 per cent of patients in both groups. Identical. The drug, in the trial’s terms, was no worse than placebo on the one risk that had kept it sidelined for decades, and the result held even though three in five of the operations studied were cancer surgeries, exactly the patients most people would have hesitated over.

That cancer figure is not a footnote. People with cancer are often quietly excluded from trials like this, despite making up a large slice of everyone who ends up in an operating theatre.

There are limits to read into it, of course. This was ten hospitals in one country, the transfusion reduction is real but modest in absolute terms, and a cluster trial of this kind measures what a hospital-wide policy does rather than what happens to any single patient on any single day.

Cheap Drug, Profound Sums

Still, the economics are hard to wave away, and the researchers clearly know it. “One transfusion in Canada costs more than $700 CAD, compared to under $10 for tranexamic acid,” says Ryan Zarychanski, the trial’s chair and a critical care physician at the University of Manitoba. He estimates routine use in major non-cardiac surgery could save 50,000 units of blood a year in Canada alone, and millions more worldwide. His co-author Daniel McIsaac, an anesthesiologist at The Ottawa Hospital, puts the Canadian figures another way: a 25 per cent annual drop in patients needing a transfusion, and a 10 per cent fall in the blood units required. Blood, it is easy to forget, is not a manufactured commodity. It comes from donors, it is perpetually in short supply, and every unit not spilled on a table is a unit available for someone else.

What happens next is less about evidence than about habit. A drug this old and this cheap has no marketing budget, no sales force, nobody whose job it is to nudge it into operating rooms where it isn’t already standard. “We hope our findings will reassure care providers that this drug is safe and effective at reducing bleeding and remove a barrier to its use in most major surgeries,” says Dean Fergusson, a senior scientist at The Ottawa Hospital and one of the trial’s senior authors. Whether that reassurance actually changes what surgeons do, ward by ward and country by country, is the experiment that starts now.

Houston, B. L., et al. New England Journal of Medicine (2026). DOI: 10.1056/NEJMoa2515820

Frequently Asked Questions

Why would a drug that helps blood clot be considered risky for surgery?

Tranexamic acid reduces bleeding by stopping the body from breaking clots down too fast, which is helpful during an operation but raises a logical worry: clots could form in the wrong place, such as a deep vein or the lungs. That concern was strongest for cancer patients, who already carry an elevated clotting risk. This trial found no increase in such clots, which is precisely why the result matters.

How much blood could routine use actually save?

In the trial, about ten units of red cells were saved for every hundred patients treated. Scaled up, the researchers estimate routine use in major non-cardiac surgery could save roughly 50,000 units of blood a year in Canada alone, with millions more worldwide. Given that donated blood is chronically in short supply, that is a substantial dividend from a very cheap drug.

If the drug is so cheap and old, why isn’t it already used everywhere?

It has been standard in cardiac and some orthopedic surgery for over three decades, but uncertainty about clotting risk kept it out of many other major operations, especially cancer surgery. There was simply no large, definitive trial showing it was safe across the board. This study was designed to remove that doubt and, with it, the main barrier to wider adoption.

Does this mean every surgery patient should now get it?

The findings support expanding use to major surgeries where patients face a high risk of significant blood loss, which is the population the trial actually studied. It is not a blanket recommendation for every minor procedure. As ever, the decision rests with the surgical and anesthesia team weighing an individual patient’s circumstances.

Editor’s note: This article was updated on September 14, 2026, to align its headline and wording more closely with the evidence and sources.