Some info on GHB
"The drug can take anything from 10 minutes to an hour to take effect, so wait until the first hit kicks in before taking any more. Its strength varies wildly, so always take a small amount first. Because of it's disabling effects, you are exposed to the threat of sexual assault, so be very, very wary of who you're with.
Increasingly, there have been reports of the drug being used as a 'date rape' drug (like Rohypnol), with victims being slipped the drug via alcohol, or in coffee, tea or hot chocolate (it is almost tasteless).
A Home Office report in June 2000 questioned 123 victims of such drug assisted assaults, and found that 70% of the rapists were known to the victim and 12% were given the drug in their home, 10% on a university campus. One in five victims could not remember the assault while around 70% felt physically unable to resist (source: Guardian 22.06.00).
Health risks: unknown at present, although there have been reports of people suffering convulsions and collapsing and a recent fatality in the UK (Oct 97). urban75 has received several reports of users being hospitalised with stomach and breathing problems, although there is almost always other drugs involved.
The drug, which is derived from an American anaesthetic, lowers blood pressure and in some cases people find breathing difficult. Overdosing can lead to a loss of consciousness and coma. It is not recommended that asthmatics or those with any form of respiratory or low blood pressure disorders take this drug. "
More info at link
http://www.urban75.com/Drugs/gbh.html