Police are warning of the dangers of spiked drinks after at least four people were hospitalised by a substance designed as an anaesthetic.

Officers from South Yorkshire Police believe the four people who were treated at Rotherham District General Hospital, had "liquid ecstasy" poured into their drinks.

One woman ended up in intensive care after falling victim to the substance, known as GHB and originally developed as an anaesthetic.

GHB is odourless and colourless, and produces similar effects to alcohol.

GHB is also known as a "date rape" drug

But the substance can also induce vomiting, unconsciousness and even death, and is often classed as a "date-rape" drug.

A spokeswoman for South Yorkshire Police said: "It appears that somebody with a dubious or malicious motive has been spiking drinks.

"Police are warning the public to be wary of being passed any drinks when the origin is unknown and to be careful about leaving any drinks unattended.

"If in doubt, don't drink it."

Those taken to hospital include a 26-year-old woman who ended up in intensive care, and a couple who were brought into the hospital unconscious.

In May, a 36-year-old man was treated for the same effects.

GHB is to be banned after a recommendation last year by the Advisory Council on Misuse of Drugs.