A study based in London found that an active ingrediant in chocolate could help ease persistent coughs in humans and could be used in medication in the near future.

The substance, theobromine, is naturally found in cocoa. Researchers said theobromine is one-third more effective at treating coughs than codeine which is commonly used in many medications today.

Professor Peter Barns of ICL and Royal Brompton Hospital was pleased with the study's results. 'While persistent coughing is not necessarily harmful it can have a major impact on quality of life, and this discovery could be a huge step forward in treating this problem.'

Dame Helena Shovelton, chief executive of the British Lung Foundation, says: 'The results of this research sound very promising. Persistent coughing often affects lung disease patients so this could be a progressive step in treating it.'

It could still be some time before regular medication is developed using theobromine.

There are two major advantages to theobromine over codeine: first, there are no side effects like drowsiness and second: it tastes a heck of a lot better.