Lemon juice 'could stop Aids'

The common lemon - a cure for the HIV virus?

Australian scientists have provoked controversy by suggesting lemon juice could act as a cheap and effective birth control and help stop the spread of the deadly Aids virus.

Reproductive scientist Roger Short, from the University of Melbourne, said laboratory tests have shown that lemon juice killed sperm and HIV, which often develops into Aids.

Lemon juice is very effective in immobilising human sperm and also very effective in killing HIV

Roger Short, scientist

Speaking on the Australian television programme Catalyst, Mr Short said lemons could be an alternative to costly HIV-drugs and traditional forms of contraceptives in developing countries.

According to Mr Short, lemons could be used as a contraceptive by soaking a piece of cotton wool in the juice and inserting it into the vagina before sex.

"We can show in the lab that lemon juice is very effective in immobilising human sperm and also very effective in killing HIV," he said.

Medieval roots

The practice of using lemon juice to prevent pregnancy was commonly used in medieval times, including by the legendary lothario Casanova, but has been forgotten by modern medicine.

Casanova used lemon juice as a contraceptive

"About 300 years ago, Mediterranean women used lemon juice as their main method of contraception," said Mr Short.

His findings have been challenged by other scientists, who warned of the potential of damaging side-effects.

"It's possible that he's [Mr Short] onto something but it clearly needs to be followed up in clinical trials in humans," said Andrew Grulich, from the Australian Society for HIV Medicine.

"The acidity is something that may well help inactivate and kill HIV, but we also need to be concerned that the level of acidity might also damage the vaginal lining and allow an entry point for HIV," said Mr Grulich.

Mr Short said he planned to carry out tests in the method in Thailand.

Julian Meldrum, international editor of Aidsmap, told BBC News Online that the principle behind the theory seemed like good science.

In fact, two similar substances were currently in tests.

However, he said: "There is not yet enough evidence that this will be safe and effective in practice.

"Before anyone goes around promoting this as an idea, we need proper, thoroughly carried out studies.

"We also need to examine whether it is safe to put what is quite a strong acid into contact with mucus membranes which are quite delicate."