Clubbers have been warned against taking a potent mixture of 'clubbing drugs' following the death of a man.
Police say mixing drugs can be fatal
The 25-year-old fell ill at a Vauxhall nightclub, in south west London, in the early hours of Sunday, police said.
He was found unconscious the next morning and died on Tuesday in a south London hospital on Tuesday.
Police believe the drugs, often referred to as 'G', are popular on the gay scene. Five other incidents due to drugs are being investigated.
Det Insp Dave Willis of Southwark CID said: "At this stage, we believe he fell ill after using either GHB (Gamma hydroxy butyrate) or GBL (Gamma butyrolactone) both of which are increasingly popular on the gay club scene and are frequently referred to as "G".
"Friends have told us that during the evening, the deceased man mentioned taking a combination of GHB/GBL and other "recreational" drugs," he said.
Supt Alistair Sutherland, from Kennington Police, said: "People are not aware of the potentially fatal reaction it can have on their bodies especially when mixed with other recreational drugs and alcohol."
In the past two months 15 collapses and two deaths related to the drugs have been reported in south west London, police said.