Merely thinking of chocolate may set pulses racing, but research suggests it can actually lower blood pressure.
Daily consumption of dark chocolate or cocoa powder caused a slight reduction in blood pressure readings, a review of study evidence showed.
Although the effect was small, it was potentially enough to help protect people from heart disease, said experts.
Scientists analysed data from trials in which people consumed daily helpings of dark chocolate or cocoa powder. The chocolate products contained varying amounts of plant compounds called flavanols that are believed to benefit health.
A total of 856 people took part in 20 trials lasting an average of two to eight weeks. The most flavanol-rich chocolate or cocoa was found to lower blood pressure by an average of two to three millimetres of mercury.
When chocolate or cocoa powder was compared with flavanol-free products, the beneficial effects were more pronounced. In this case, blood pressure reductions of up to four millimetres of mercury were seen. The findings are published in the latest issue of The Cochrane Library, a collection of studies aimed at informing health care policy.
Lead researcher Dr Karin Ried, from the National Institute of Integrative Medicine in Melbourne, Australia, said: "Although we don't yet have evidence for any sustained decrease in blood pressure, the small reduction we saw over the short term might complement other treatment options and might contribute to reducing the risk of cardiovascular disease."
Flavanols in cocoa, the raw material from which chocolate is made, are believed to boost levels of nitric oxide in the body. This in turn causes blood vessels to relax and widen, thereby reducing blood pressure, say scientists.
The British Heart Association warned of the downside of eating chocolate - large numbers of calories. Victoria Taylor, senior dietician at the charity, said: "With most of the studies carried out over a short period of time it's also not possible to know for sure whether the benefits could be sustained in the long term.
"The 100g of chocolate that had to be consumed daily in a number of the studies would also come with 500 calories - that's a quarter of a woman's recommended daily intake. Beans, apricots, blackberries and apples also contain flavanols and, while containing lower amounts than in cocoa, they won't come with the unhealthy extras found in chocolate."