Cape Town: The world's oldest bed, dating back 77,000 years, has been discovered in a cave in South Africa.

The bed, made of bundles of sedge and wild quince leaves, was found by archaeologist Lyn Wadley of Wits University, while excavating a site at Sibudu in KwaZulu-Natal province, as reported.

The site was a rock shelter on a cliff face on the banks of the Thongathi river, 40 km north of Durban, where Wadley has been working as an archaeologist since 1998.

Wadley found the bed (about 1x2 metres in size) buried more than three metres deep in sediments.

What was special about the bed was that it was covered with a layer of aromatic leaves from a plant called the river wild quince. No other tree leaves were found on the bedding, so the leaves were not there as a result of random leaf fall, the report said.

The leaves of the river wild quince have insect-repellent properties, especially against mosquitoes, so these bed-makers clearly had a good knowledge of herbal medicine, it said.

There was also evidence at the site that bedding was occasionally burnt, presumably to get rid of residual bugs.

The bed-makers were Middle Stone Age humans, skilled in making stone tools, including spearheads, knives and scrapers, as well as perforated-shell jewellery.

They also made bone tools and mixed ochre -- natural earth containing ferric oxide, silica, and alumina -- which might have been used as an insect repellent or as paint.

Before this extraordinary discovery, the earliest known beds were about 25,000 years old, and the earliest known use of herbal medicine was about 5,000 years ago.