A small bar of dark chocolate a day helps keep stress at bay, say researchers.
It cuts levels of stress hormones and rebalances other chemicals in the body during times of high anxiety, a study found.
A group of men and women ate 20g of dark chocolate - roughly half a small bar - morning and evening and scientists monitored their stress hormone production. The high hormone levels in those under the most pressure fell after just two weeks of chocolate therapy, the Journal of Proteome Research reports.
Researcher Sunil Kochhar, who works for Nestle, said the study by Dutch and Swiss scientists 'provides strong evidence that a daily consumption of 40g is sufficient to modify the metabolism of healthy volunteers'.
He added that stress reduction has long-term health benefits.
Other recent research has shown that just a 6.7g chunk of dark chocolate a day - a quarter of an ounce - could cut the risk of heart disease by up to a third.
The benefits were attributed to flavanols, plant chemicals that cut inflammation linked to heart disease, as well as reducing blood clots and helping to keep diabetes and high blood pressure in check.
Dieticians recommend caution, however, stressing that chocolate is high in fat and sugar and should be eaten only as part of a balanced diet.