MP4OX is made from expired blood stocks and seeks to replicate the function of red blood cells in carrying oxygen around the body.
It is being given to patients with heavy blood loss in 56 centres around the world.
The Royal London Hospital is leading the clinical trials.
MP4OX has been developed by US pharmaceutical company Sangart, which is funding the trial, and is a haemoglobin-based product processed from expired blood transfusion stocks.
Haemoglobin molecules are the proteins in red blood cells which carry oxygen to muscles and tissue around the body.
In trauma patients who have undergone heavy blood loss, these molecules are in short supply, and its makers claim MP4OX can deliver an oxygen boost to organs and tissue in the body, reducing the risk of organ failure.
They say it carries no infection risk and can be given safely to all patients.
Prof Karim Brohi, of the Barts and The Royal London Hospital, is leading the trials.
"We’re giving it to people who been severely injured in car crashes, have fallen out of a window, been stabbed etc," he told BBC News.