Have high blood pressure? Australian scientists may have a new solution -- but it won't win you a lot of friends.

The secret weapon is garlic, according to a study published in the scientific journal Maturitas.

In a 12-week trial involving 50 patients, Karen Reid and a team of colleagues at the University of Adelaide discovered that those who took four capsules a day of a supplement called aged garlic extract had blood pressure around 10mmHg lower than a group given a placebo.

Reid said that garlic taken in any other way, whether raw, fresh or in powdered form, doesn't have the same effect.

"When you cook fresh garlic the ingredient which is responsible for reducing blood pressure disappears," she said.

"I think the really important point to make is that aged garlic extract as a supplement is the secret weapon for blood pressure."

Garlic has long been thought to be good for the heart, and traditional Indian Ayurvedic medicine practioners have been promoting the benefits of garlic as a preventative of high blood pressure for centuries.

"Garlic has been used as a treatment to lower blood pressure in Ayurvedic medicine for thousands of years," said Sundari Ganesh, a practioner of Ayurvedic medicine, told Reuters by phone.

But Reid said their research was the first to assess the impact of aged garlic extract, adding that it was evaluated as an additional treatment to other high blood pressure medication.

High blood pressure is a major risk factor for coronary heart disease, stroke, heart failure, peripheral vascular disease and renal failure.

The risk of disease increases as the level of blood pressure increases. High blood pressure is associated with other risks.

Around 1 billion people globally suffer from high blood pressure.