The suit, filed in the Orange County Superior Court near Allergan's Irvine headquarters, links the toxin-based drug to three deaths, including one in March of a 69-year-old Texan nurse who received injections for neck and shoulder pain.

In 2004, a seven-year-old Texan girl with cerebral palsy died allegedly after injections to control limb spasticity.

Meanwhile, this week in Arizona, a 71-year-old woman allegedly died because of Botox injections she received at a mall clinic a year ago for wrinkles around her mouth.

After the injections, the suit says, she had trouble swallowing and breathing, could not speak and lost weight until she died.

The suit also contends that Botox injections for approved uses, such as smoothing frown lines, and unapproved uses, such as treating migraines, left 12 others with disabilities ranging from blurred vision and allergic reactions to flu-like symptoms and difficulty in breathing.

Allergan spokesman Caroline Van Hove said she could not discuss the suit in particular, but stressed: 'Botox has a remarkable safety record.'

She also said its safety record had been validated in the 19 years since it was approved, by the distribution of more than 18million vials of Botox and more than 15million treatments worldwide.

Sales surpassed US$1.2billion (S$1.6billion) last year, and Ms Van Hove said serious adverse events had been reported rarely.

But several of the plaintiffs in the lawsuit ended up in hospital and now suffer from chronic, life-altering conditions.

The most common side effect cited in the suit is a loss of the ability to swallow, which causes a slow death from starvation or asphyxiation.

'Botox is causing major injuries and death, and it's well-documented but not widely known,' said Texan lawyer Ray Chester, who leads a nationwide team of lawyers involved in the suit.

The suit is believed to be the first to blame Botox for deaths, although in February, the US Food and Drug Administration (FDA) said it was reviewing reports of at least one death and other serious reactions to botulinum-based drugs, including Botox and competitor Myobloc.

The FDA warning came after consumer group Public Citizen's announcement in January that it had found reports linking 16 deaths to the use of Botox or Myobloc between 1997 and 2006.

In Wednesday's suit, the three deaths cited allegedly resulted from off-label uses, which are legal but unapproved by the FDA.

'Allergan emphasises that Botox is a miracle drug and has often compared it to penicillin,' the suit says.

'Meanwhile, Allergan obscures that Botox is a highly lethal toxin with serious and life-threatening side effects.'

LOS ANGELES TIMES