Tomorrow's World report from South Africa

TB, a potentially fatal respiratory disease, used to be controllable by modern antibiotics.

However, some strains of the bacteria that cause the disease have started to evolve antibiotic resistance, making effective drug therapy increasing difficult.

The disease kills thousands of people throughout the developing world, and is also re-emerging in industrialised countries.

Tuberculosis is a major problem in Africa

Scientists are now turning to ancient traditional remedies to combat the disease. Their efforts are featured in BBC television's Tomorrow's World on Wednesday.

In Pretoria, traditional healers like Matlakala Mosiweu use local plants to treat TB symptoms such as coughing and fever.

She said: "The plants are good because you dig them straight out from the soil, so they are fresh - everything that is from the soil is good."

A team from the University of Pretoria is working closely with healers such as Matlalaka to test the healing powers of local plants.

Among the scientists working on the project is Namrita Lall, who lost one of her relatives to the disease.

"A lot of substances that are used in modern medicine have originated from research on medicinal plants ," she said.

Deadly strain killed

The scientists have tested 20 plants to try to isolate an active compound that can be used to attack the TB bacteria.

Plant extracts are being tested in the lab

They believe they have found such a compound in a plant known as Helicrisum Orionatens.

An extract from the plant was able to kill a strain of TB that is resistant to seven major drugs.

The results are so impressive that a major drugs company has expressed an interest taking the research further.