Need a good excuse to eat that chocolate bar hidden in your desk drawer? How about this: Consuming chocolate could lower your blood pressure. A study published in the Archives of Internal Medicine (2006, vol. 166, no. 4) followed 470 elderly Dutch men for 15 years. Scientists found that men consuming more than 2.3 grams daily of foods with cocoa—such as chocolate bars, cookies, chocolate desserts, and hot chocolate—had lower blood pressure than those who ate fewer than 0.36 grams per day.

The substance responsible for chocolate's health benefits is the same one that makes black tea and red wine so good for you—antioxidant flavonoids. But not all chocolate is created equal. The darker the chocolate, the more flavonoids it contains, says Martin Schreiber, MD, the chairman of Cleveland Clinic's Nephrology and Hypertension Department. In fact, dark chocolate has more antioxidants per serving than either black tea or red wine.

So, does this mean you can eat all the dark chocolate you want? Not really. Chocolate still contains calories, and if it contains high amounts of saturated fat, it is by no means heart healthy. Even if dark chocolate lowers your blood pressure, says Schreiber, don't chuck your blood pressure medication. Just enjoy dark chocolate every now and then, he says, without the guilt.