That Valentine's box of delectable chocolates that made your heart sing last weekend also might — if it is the right type — help make it tick better and longer, scientists gathered last week in Washington said.

Raw cocoa contains flavonoids, plant-based compounds with protective antioxidants like those in green tea. The antioxidants may help decrease blood pressure and improve circulation, according to preliminary study results released at a daylong session centered on the medical uses and developmental potential of the cocoa tree.

As far back as the Mayas, the South American native tree, formally called the Theobroma cacao, inspired songs praising the liquid, which they called the "food of the gods."

For centuries, people followed the Maya and Aztec prescriptions and consumed cocoa, the ground beans of the cacao, for an array of ills.

People believed it would calm their nerves, shrink their hemorrhoids, ease their hangovers, relieve their tuberculosis symptoms and help them lose weight, said Dr. Louis E. Grivetti, a professor in the nutrition department at the University of California at Davis, who spoke at the session.

The seminar was held by the National Academy of Sciences, and its sponsors included the Fogarty International Center of the National Institutes of Health, the University of California, the Smithsonian and the chocolate company Mars.

Though chocolate's popularity as a favored sweet trumped its medicinal uses beginning in the mid-19th century, scientists turned again to investigating its health benefits more than a decade ago, financed partly by Mars. So far, researchers have begun to connect flavonoids with lowering the death rate from heart disease, said Dr. Helmut Sies, chairman of the biochemistry department at the University of Dsseldorf in Germany.

But the heart benefits of chocolate consumption are far from confirmed. Some experts point out that the fat in chocolate could be associated with deadly cardiovascular and kidney diseases.

Dr. Norman K. Hollenberg, professor of medicine at Brigham and Women's Hospital and Harvard Medical School, has cited another study showing that cocoa rich in flavonoids could help increase blood flow in the brain and in the hands and legs.

Mars came up with a patented process for cocoa, called Cocoapro, and supplied it to Hollenberg for his study.

The company is also using Cocoapro in some of its chocolate products, including the Dove dark chocolate bar, M&M's and its CocoaVia Snacks, which it has been testing on the Internet (www.cocoavia.com) since October. The snacks have 80 calories and claim to lower cholesterol.

So far, Mars, which sells about $15 billion of confections a year, is not certain now how it will tap the consumer market for disease-fighting chocolate — a powder, a bar or something else, said Dr. Harold H. Schmitz, director of science and external research at Mars.

"Most chocolate that is currently available is delightful and delicious," Schmitz said, "but not necessarily good for you. We hope that in a year or two, it is possible to change that."