Essential oils could be a cheap and effective alternative to antibiotics, even in the fight against drug-resistant hospital superbugs, Greek scientists have said.

They carried out extensive tests of eight plant essential oils and found that thyme essential oil was the most effective and was able to almost completely eliminate bacteria within 60 minutes.

Essential oils have been recognised for hundreds of years for their therapeutic properties. For example, Australian aborigines used tea tree oil to treat colds, sore throats, skin infections and insect bites and the remedy was sold commercially as a medicinal antiseptic from the early 20th century.

However even today, very little is known about how these oils exert their antimicrobial effects in humans. An antimicrobial is a substance that kills or inhibits the growth of micro-organisms, such as bacteria and fungi.

Various scientific studies have demonstrated that essential oils are not only well tolerated, but are effective against a range of bacterial and fungal species. Their therapeutic value has been shown for the treatment of a variety of conditions, including acne, dandruff, head lice and oral infections.

According to Prof Yiannis Samaras and Dr Effimia Eriotou of the Technological Educational Institute of Ionian Islands, their study revealed that thyme and cinnamon were particularly efficient antibacterial agents against a range of Staphylococcus species.

Strains of these bacteria are common inhabitants of the skin and some may cause infection in people with compromised immune systems. Drug-resistant strains, such as meticillin-resistant Staphylococcus aureus (MRSA) are extremely difficult to treat.

"Not only are essential oils a cheap and effective treatment option for antibiotic-resistant strains, but decreased use of antibiotics will help minimise the risk of new strains of antibiotic resistant micro-organisms emerging," explained Professor Samaras.

The scientists believes essential oils could have diverse medical and industrial applications.

"The oils, or their active ingredients, could be easily incorporated into antimicrobial creams or gels for external application. In the food industry the impregnation of food packaging with essential oils has already been successfully trialled. They could also be included in food stuffs to replace synthetic chemicals that act as preservatives," they said.

Details of this research were presented at the Society for General Microbiology's spring meeting in Edinburgh this week.