Drinking to excess may help you forget but moderate alcohol consumption could actually make memories more painful, claim scientists.
Researchers found suffering a trauma after one or two drinks meant your brain remembered only snapshots without the "context" that made them more understandable.
That meant the memory was more painful and more likely to cause distress, said the scientists at University College London.
However in those that have drunk seven or more units of alcohol - four or five drinks - the memory was completely obliterated.
"Many people who experience a personally traumatic event such as rape or a road traffic accident have consumed alcohol beforehand," said James Bisby who led the research.
"For the first time, this research gives us an idea of how being under the influence of alcohol might contribute to our wellbeing later on.
"Drinking moderately seems to show that you get more flashbacks and you have lost the context and the control over the memory."
During the study, nearly 50 participants consumed either alcohol or a soft drink and then performed a virtual reality task designed to examine how an experienced event is stored within memory.
They were then shown a video of serious road traffic accidents and recorded the number of times they spontaneously re-experienced any of the footage or had a flashback, over the following seven days.
The authors of the study found that "contextual memory" is reduced in those who experience high levels of stress and this reduction may be exaggerated in those who have had a couple of glasses of wine (around three units).
This results in more involuntary and distressing flashbacks.
The researchers, who published their findings in the journal of Biological Psychiatry, said drinking to forget was not always the best option.
"When people have no memory of the traumatic event, as can happen if they consumed a large amount of alcohol beforehand, they are more likely to imagine a 'worse case scenario'", said Professor Valerie Curran, a co-author of the research.