'Laughing gas' clubbers taken to Bolton hospital
Three people were hospitalised after a reaction to inhaling "laughing gas", Greater Manchester Police said.
Two men and a woman were admitted to the Royal Bolton Hospital after inhaling nitrous oxide and were said to be "recovering well".
Police, who were called to the hospital at 04:00 BST, said the three had been at the La Spatule club on Bradshawgate.
Inspector Graham Neild said: Our initial inquiries have established they may have inhaled nitrous oxide."
He said the police investigation was continuing.
Nitrous oxide, inhaled from a balloon, gives users a sense of euphoria that lasts a short time.
But the health risks are caused as the gas displaces air in the lungs, depriving the body of oxygen.
According to medics it also comes with effects such as nausea, vomiting, and occasionally convulsions.
Earlier in the summer, The Home Office urged music festivals to crack down on its use.
Minister for Crime Prevention Norman Baker wrote to festival organisers warning of its potential dangers.
It is illegal to sell the gas to under-18s if it is expected they will ingest it to become intoxicated - and people have died following reactions to the gas.