How many times have you wished you could simply delete a bitter memory from your mind? It seems that science may have found a way to do just that.

Researchers at Harvard and McGill University in Montreal are working on an amnesia drug that blocks or deletes bad memories. The technique seems to allow psychiatrists to disrupt the biochemical pathways that allow a memory to be recalled, reports LiveScience.

In a new study, published in the Journal of Psychiatric Research, the drug propranolol is used along with therapy to "dampen" memories of trauma victims. They treated 19 accident or rape victims for 10 days, during which the patients were asked to describe their memories of the traumatic event that had happened 10 years earlier. Some patients were given the drug, which is also used to treat amnesia, while others were given a placebo. A week later, they found that patients given the drug showed fewer signs of stress when recalling their trauma.

Similar research led by Professor Joseph LeDoux has been carried out at New York University on rats; scientists were able to remove a specific memory from the brains of rats while leaving the rest of the animals' memories intact. An amnesia drug called U0126 was administered.

The rats were trained to associate two musical tones with a mild electrical shock so that when they heard either of the tones they would brace themselves for a shock.

The researchers then gave half the rats the drug when playing one of the musical tones. After the treatment, the rats that had been given the drug no longer associated that particular tone with an imminent shock but still braced themselves upon hearing the second tone, demonstrating only one memory had been deleted.

Science fiction fans have a number of associations with the idea of banishing unwanted memories.

In the 2004 film Eternal Sunshine of the Spotless Mind, Kate Winslet and Jim Carrey play lovers who have a falling out. Winslet's character goes to a company called Lacuna, Inc. to have her memories of the relationship removed; Carrey's character also has the procedure performed.

In the film, the process involves showing the person a memento of the relationship and then encouraging them to bring up specific memories while an electric shock is given. Not to give away the film, but this technique does not work as planned.