A drug once used to treat stomach ulcers may help to boost brainpower in old age, a study suggests.
There are no effective treatments for dementia at present
Researchers at the University of Edinburgh carried out tests on 22 men between the ages of 52 and 75.
Some of the men were given a drug called carbenoxolone and others were given a dummy drug.
Writing in the Proceedings of National Academy of Sciences, they said those on carbenoxolone had better memory and verbal skills after just six weeks.
Carbenoxolone is derived from liquorice root. It used to be prescribed by doctors to treat stomach ulcers. However, it has since been replaced by more effective drugs.
The drug is known to block a chemical called 11 beta-hydroxysteroid dehydrogenase type 1.
Studies have suggested that this chemical is involved in the production of a key hormone - glucocorticoids - in the brain, which has been linked to brainpower.
Professor Jonathan Seckl and colleagues carried out tests to see if blocking this chemical could boost memory and verbal skills.
They enrolled 10 healthy men and 12 men with type 2 diabetes in their study. People with diabetes are more likely to suffer poor memory or dementia.
The men were given either carbenoxolone or a dummy drug three times a day.
Tests carried out after four weeks showed that verbal skills had improved in those who had taken carbenoxolone.
After six weeks, the researchers found that verbal memory had also improved in those men with type 2 diabetes. Those on carbenoxolone did not appear to suffer any side-effects.
The researchers said studies should be carried out to see if carbenoxolone could be used to help people suffering from dementia and other similar conditions.
"The findings are very encouraging," Professor Seckl told BBC News Online.
"What we now need to do is to move from these small preliminary studies to a much larger study involving a larger group of patients."
He said if the studies proved successful it could pave the way for carbenoxolone to be used to treat dementia.
"It would be dealing with a massive unmet need. There is nothing very useful for people with memory impairment at the moment."
Harriet Millward, deputy chief executive of the Alzheimer's Research Trust, welcomed the study.
"This new research is very interesting and is a good step along the way to developing possible future treatments or preventions for Alzheimer's disease.
"The study is fairly small and will need replicating on a larger scale so the results can be confirmed."