Hibiscus tea can lower blood pressure as effectively as pharmaceutical drugs, numerous studies have shown.

An herbal tea (tisane) made from hibiscus flowers is a popular beverage worldwide. The ruby-colored, tangy drink is known as "jamaica" in Mexico and is the primary ingredient in Red Zinger tea.

"Most of the commercial herbal tea blends in the United States contain hibiscus," said Diane L. McKay of Tufts University, who has researched the blood pressure reducing benefits of the flower.

Hibiscus (Hibiscus sabdariffa) actually has a long history of use as a blood pressure treatment in many African and Asian traditional medical systems. In the late 1990s, Iranian researchers clinically demonstrated the effectiveness of this treatment. They assigned 54 adults with high blood pressure to drink 10 ounces of either or hibiscus tea or black tea once a day for 12 days. They found that while blood pressure decreased in both groups, it decreased significantly more in the hibiscus group (a total of 10 percent).

This was followed by a pair of studies that compared with hibiscus tea directly to pharmaceutical blood pressure drugs. In 2004, Mexican researchers assigned 75 adults with high blood pressure to take either 25 mg of the drug captopril twice per day, or to drink tea made from 10 g (about 5 teaspoons) of crushed dried hibiscus once per day. After four weeks, blood pressure had dropped by 11 percent in both groups.

In 2007, the researchers conducted a follow-up study, this time using the blood pressure drug lisinopril as a comparison. Once again, hibiscus performed comparably to the drug, reducing blood pressure in hypertension patients in average of 12 percent, compared with 15 percent for lisinopril.