Two British tourists were hospitalised after a bartender served them cleaning agent instead of alcohol in Greece.
They are among five men, all aged between 35 and 69, who became seriously ill moments after taking a shot of the detergent.
The incident happened at a luxury hotel in the village of Gouves, in Crete, in the early hours of Saturday, as the group was partying with the bar staff.
It is understood that the bartender served liquid from a bottle she had found in the fridge.
She also poured a glass for herself but did not have time to drink it as the hotel guests felt unwell.
All five were rushed to hospital, where they were placed in the intensive care unit.
Four of them were taken to the University Hospital of Heraklion, where they are intubated and mechanically supported.
Local media reported that the hotel manager was arrested as police launched an investigation into what happened.
Meanwhile, the liquid has been confiscated and will be checked by authorities, but preliminary tests showed it to be a cleaning detergent.
The bar has also been closed while the probe is carried out and local health and safety authorities have been called in.
