Holiday-makers heading for Ibiza's famed clubs are being warned to steer clear of a potentially lethal drug which is causing two people a day to lapse into comas. The colourless, odourless anaesthetic known as liquid ecstasy can cause sickness, fits and comas and is responsible for 12 deaths in Britain. GHB short for gammahydroxbutyrate can be fatal when mixed with alcohol. In a report for the BBC One's 4x4 current affairs programme, researchers found as many as two coma patients a day are being treated in the island's main hospital for the effects of the liquid ecstasy. Revellers can unwittingly overdose on the drug, which is being dissolved in bottles of water and passed around clubs.