It has been blamed for everything from food poisoning to John Kerry's wrinkle-free face, but Australian researchers say botox could now be a cure for incontinence.

A study at Queensland's James Cook University found the toxin could reduce the bladder activity of test patients fivefold.

Three women who have multiple sclerosis and overactive bladder condition (OAB) had botox injections every eight to 12 weeks to reduce the activity of the detrusor muscle. This usually forces out urine only when the bladder is full, but is overactive in people suffering from OAB.

"They became totally continent. They have tremendous improvement in their quality of life and only go to the toilet five or six times a day," said Ajay Rane, obstetrics and gynaecology professor at James Cook University.

The patients, who use wheelchairs, had previously been urinating up to 20 times a day and seven times a night.

OAB is normally treated with antimuscarinics, a class of drugs that have recently been linked to a higher risk of Alzheimer's.

Botulinum toxin A, a poisonous chemical released by the bacteria which cause botulism, is better known for its use in celebrity makeovers, where its muscle-paralysing abilities reduce the appearance of wrinkles. The treatment costs £700 a time, but Prof Rane believes medical licensing would cut costs.

Doctors have also recommended botulinum as a cure for a range of disorders, such as muscle spasms, problem sweating and anal fistulas.