Worldwide, millions of people are treated each year for severe head injury. A substantial proportion die, and many more are permanently disabled. If short term corticosteroid infusion could be reliably shown to reduce these risks by just a few percent then this might affect the treatment of a few hundred thousand patients a year, protecting thousands from death or long term disability.

When all previous trials of steroids in head injury are combined, the risk of death in the corticosteroid treated group appears to be about 2% lower than in the control group, but the 95% confidence interval runs from 6% lower to 2% higher mortality. Thus, the overall result is compatible with there being no benefit, but is also easily compatible with a benefit of a few percent.

The CRASH trial will determine reliably the effects on death and on disability of a short term corticosteroid infusion following significant head injury.

To detect or refute improvements of only a few percent in outcome, many thousands of acute head injury patients must be randomised between control and steroid infusions. Such large numbers will be possible only if hundreds of doctors and nurses can collaborate in the participating emergency departments. Since they are busy, and working in emergency situations, the trial involves them in almost no extra work: no special investigations or changes to usual management are required, and data collection is absolutely minimal.  Patients participating in this trial are not precluded from enrolment in other trials.