Chocolate may offer relief to people suffering from a persistent cough, according to scientists who found that a compound in cocoa was effective in reducing symptoms of both acute and chronic coughs.

Previous research at the National Heart and Lung Institute in the UK showed that the cocoa ingredient called theobromine was even more effective than the widely used drug codeine in blocking the action of the sensory nerves that triggers the cough reflex.

Scientists, presenting their latest research at the British Thoracic Society's winter meeting in London last week, studied 300 people with a persistent cough in a clinical trial at 13 public hospitals in the UK.

Researchers gave participants the naturally occurring chemical theobromine, extracted from the raw ingredient of chocolate, twice a day for two weeks.

The study found that 60 percent of the patients in the study experienced some measure of relief, leading researchers to suggest that a daily bar of dark chocolate may contain enough of the active compound theobromine to appease a chronic cough.

While the news may be sweet, researchers noted that chocolate is not a cure because they found that symptoms returned once treatment ended.

A persistent cough (chronic cough) is a cough that lasts eight weeks or longer. Some of the symptoms of coughing include loss of sleep, sore chest muscles and leaking urine. In severe cases, a chronic cough can lead to vomiting, rib fractures and lightheadedness.

While it is sometimes difficult to pinpoint the exact cause of the condition, the most common causes of chronic cough are tobacco use, postnasal drip, asthma and acid reflux or the backflow of stomach acid, which can irritate a person's throat, according to the Mayo Clinic. Experts say that persistent cough typically disappears once the underlying problem is treated.

In the study, participants were given a single dose of 1,000mg of theobromine. However, an unsweetened dark chocolate bar contains about 450mg per ounce, sweet dark chocolate contains around 150mg and milk chocolate contains about 60mg.

"This new capsule we are using seems very effective," said Principal investigator Professor Alyn Morice, head of the Hull Cough Clinic, according to the Daily Mail.

"Eating a bar of dark chocolate a day which has high levels of the compound may also be effective for people with diagnosed persistent cough, although eating chocolate on a daily basis may have other unwanted effects, including weight gain and so on," she concluded.