Los Angeles: Four people suspected of contracting botulism after receiving Botox injections were critically ill last night.

It is thought they caught the potentially fatal illness, which causes breathing difficulties and muscle weakness, from a tainted batch of the anti-wrinkle treatment at a clinic in Fort Lauderdale, Florida.

At least two of the patients – a married couple in their 50s – are on life-support machines.

‘This is a severe adverse reaction, most likely due to a contaminated vial, ‘ said Dr Charles Schallop, a neurologist at Palm Beach Medical Centre where they are being treated.

The other victims – a doctor and his girlfriend – are in hospital in New Jersey.

Botox is a sanitised form of the food poisoning bacteria botulinum toxin. Cosmetic surgeons have harnessed its muscle-paralysing ability to smooth furrowed brows and make patients look younger.

Hospitals have been warned to look out for symptoms of botulism in Botox users.