Experts have uncovered more evidence that Botox could be an effective treatment for an overactive bladder.
Injecting the the toxin directly into the wall of the organ was found to improve symptoms among women considered to have a "weak" bladder.
On average, the number of times they suffered an episode of incontinence fell from six times a day to under once a day.
The number of times they felt an urgent need to go to the toilet also fell, from around eight times a day to three times a day.
About four out of 10 women treated with Botox became continent again after six weeks and a third were still continent six months after treatment. The effects started to wear off after about six months.
The study, published in the journal European Urology, was carried out at eight urogynaecology centres in the UK from 2006 to 2009.
A total of 240 women were split into two groups, with 122 women given Botox and 118 receiving a dummy treatment.
Researchers found improvements across a range of symptoms, including wetting oneself, feeling a need to rush to the toilet, and how often the women "leaked" urine.
However, there were side-effects - including some women needing to use a catheter to go to the toilet because of paralysis in the bladder muscle.
It is unclear how many people in the UK suffer urinary incontinence, but it is thought to affect more than 50 million people in the developed world.
Figures from a previous UK study found that 13% of women and 5% of men had some degree of urinary incontinence. Women are more at risk, owing in part to the effects of childbirth.
Current treatments include pelvic floor exercises, behavioural therapy and drugs that can have side-effects, such as a dry mouth, constipation and blurred vision.
Dr Douglas Tincello, senior lecturer from the University of Leicester and honorary consultant gynaecologist at University Hospitals of Leicester NHS Trust, led the latest study.
He said some patients affected by the condition "find it hard to cope", adding: "One patient told me of a harrowing situation whereby she ended up passing water over a supermarket floor."
He continued: "We found that a single treatment with botulinum toxin was a very effective treatment for the symptoms; patients were able to pass water one or two times less often during the day, and also noticed far fewer times when they had bad feelings of urgency and had to rush to the bathroom.
"In patients treated with botulinum toxin, incontinence episodes dropped from six a day to less than once a day.
"The number of urgency episodes fell from eight a day to three a day at six weeks. These changes were maintained at a similar level for up to six months.
"The treatment is not without complications; about one in eight women had some difficulty emptying their bladder at some time in the six months after treatment (due to paralysis of the bladder muscle).
"This was treated by teaching the women to use disposable catheters, but the effect does wear off after about six months on average."
Dr Tincello said he was "excited" by the results of the trial, saying Botox "works so much better than the drugs we have."
He continued: "My patients have been delighted with how well it works, even with the chance of needing to use a catheter.
"I'm delighted to say that botulinum toxin has much better results than a six-month course of tablets or bladder training.
"Our work may lead to Botox being licensed to treat overactive bladder syndrome in the UK."
The study was funded by the Moulton Charitable Trust, Wellbeing of Women and the Rosetrees Trust, and is the largest of its kind into Botox not to be funded by drug firms.
Liz Campbell, director of Wellbeing of Women, said: "This is a horrible condition and often means otherwise healthy active women curtail their lives, becoming prisoners in their homes.
"It is rarely discussed but affects many women."