GHB is used by date rapists

In the most recent case a woman collapsed in a pub toilet and was taken to hospital semi-concious despite having little to drink.

The other victim, 25, told a local newspaper she was taken to hospital after collapsing in the street.

She said: "I remember drinking a glass of wine and then there was nothing. My friends told me that I went very sleepy."

Police in Cardiff are now warning women drinkers in particular to take extra care.

Detective Sergeant David Goddard said he did not not want to alarm people.

But he advised women not to accept drinks from people they do not know, and never to leave drinks unattended.

"We want people to take sensible precautions," he said.

"If you have to leave your drinks ask a friend to keep an eye on them."

Two women in Cardiff have had their drinks spiked

Meanwhile a campaign has been launched to warn clubbers about the dangers GHB - also known as liquid ecstasy.

Julie Eason of the charity, Release, says clubs have reported a big increase in the use of the drug.

Release has called for the government to ban the drug which is popular with clubbers and also linked to cases of women being sedated and raped.

After emerging on the gay scene in the early 1990s and being taken up by bodybuilders, the drug moved into dance clubs.

Dt Sgt David Goddard advised sensible precautions

Release called the drug "more dangerous than Ecstasy" and said Britain should follow the lead of President Bill Clinton, who signed a law banning GHB in February after it was linked to 60 deaths in the United States since 1990.

The colourless, odourless drug - legal in Britain - is sold in sex shops, through mail-order and over the internet and is sometimes used to ease sleeping disorders.

It can knock users unconscious and be lethal when mixed with alcohol.

Sexual assault victims whose drinks are spiked often have no memory of the attack.

In the run-up to summer music festivals across Britain, Release said it was blanketing clubs and drug agencies with leaflets spelling out the effects and dangers of GHB.