If you’re dealing with a nasty cough, forget about codeine and even honey and lemon (ok, maybe not honey). One of the easiest and undeniably tastiest way to quiet that hack is by eating chocolate, according to a Hull University professor.
Professor Alyn Morice, head of cardiovascular and respiratory studies at Hull, said there’s a lot of truth to a new study that tested the efficacy of a chocolate-based cough medicine. The study will be published later this year.
Morice was not involved in the study, but he is “an international authority on cough and the mechanism of cough.” He is also a founding member of the International Society for the Study of Cough.
The study, ROCOCO, involved 163 patients who were randomly given either linctus (a cough medicine in syrup form) or a chocolate-based cough syrup called Unicough.
Participants’ cold and cough symptoms improved dramatically after just two days of using Unicough. The study also found that Unicough worked better than conventional cough medications. Twice as many patients were able to stop treatment early because their cough had improved so much. 
The power of the cocoa-based concoction seems to lie in the demulcent properties of cocoa. The texture of chocolate makes it more viscous than traditional cough medicines, which allows it to coat the throat and soothe the urge to cough.
While the combination of honey and lemon does basically the same thing, Morice said chocolate likely has a “pharmacological activity, some sort of inhibitory effect on the nerve endings themselves.”
Morice wrote in the Daily Mail:
“We have just seen the results of the largest real-world study of an over-the-counter cough remedy ever undertaken in Europe. This proves that a new medicine which contains cocoa is better than standard linctus. The head-to-head comparison found that patients taking the chocolate-based medicine had a significant improvement in symptoms within two days.” 
Morice also said:
“I know that might sound like something out of Mary Poppins, but as an independent clinician who has spent years researching the mechanism of cough, I can assure you the evidence is actually as solid a bar of Fruit and Nut.”
Previous studies have shown that chocolate is effective at treating coughs. One study conducted by researchers at Imperial College in London showed that theobromine, an alkaloid in cocoa, suppresses cough better than codeine.
If the idea of any cough medicine turns you off, Morice said that slowly sucking on a piece of chocolate may provide some relief, although the syrup is more effective because of “other cough-fighting compounds.”
And sipping hot cocoa won’t do much to help a cough because you swallow it too quickly and it doesn’t have a chance to adhere to the interior of your throat and protect the nerve endings. 
 Daily Mail