Trials using the herbal extract ginkgo biloba to treat tinnitus have shown it is no more effective than a placebo.

Many tinnitus sufferers believe the herbal extract can cure the condition.

But when a clinical trial which recruited its 720 participants from across the UK gave half ginkgo, and half a placebo, the extract had no discernible effect.

The trial was funded by one of the main companies which makes ginkgo extract, German Lichtwer Pharma, and backed by the British Tinnitus Foundation.

'Ringing in ears'

In both the group taking ginkgo and those taking the placebo, 35 of 360 saw improvements in their tinnitus over a 12-week course.

Tinnitus is described as "ringing in the ears".

It can be a symptom of a disease, but its precise cause is not fully understood.

It is commonly thought just to affect the elderly, but people of all ages can have the condition. Mild tinnitus affects around 10% of the UK population.

Herbal remedy

Ginkgo has been used in Chinese medicine for thousands of years and is now commonly available in UK health food shops.

It had been thought it could be a possible cure for tinnitus because it can help people with cerebral insufficiency, who have poor blood supply to the brain.

Symptoms can include absent-mindedness - and tinnitus. In those cases ginkgo can help

Previous trials looking at the effect on people who just had tinnitus produced varying results.

But University of Birmingham research associate Shelley Drew, who led the trial, said ginkgo could have helped tinnitus in those people as a side effect of helping the cerebral insufficiency because it has an effect on the cardiovascular system.

If people are stretched financially, I wouldn't advise them to take it

Shelley Drew University of Birmingham

She told BBC News Online: "Most people with tinnitus have some sort of hearing loss."

She said of ginkgo biloba: "If people are stretched financially, I wouldn't advise them to take it. But if someone wanted to try it, it is pretty harmless."

Ms Drew said lots of people with tinnitus had gone through the many different brands of ginkgo biloba to try and find the most effective one.

A spokesman for the British Tinnitus Association said: "No research had really been done in this area using a large amount of people, and as a properly controlled trial.

"This trial showed the placebo was just as good as the substance, and in some ways it's good because at least it does give an answer."