Police have warned a substance which caused youths in Co Antrim and Co Down to fall ill, may be circulating in other parts of Northern Ireland.
They are working with their partners in public health to alert parents, guardians and young people of the potential dangers.
In a Facebook post, police said they are investigating reports in Ballyclare, Antrim and Newry of young people becoming ill after inhaling a substance from a vape type device.
"We would urge anyone using vape devices to only use liquids obtained from reputable sources," a police spokesman said.
"People under 18 years of age should not be using these devices as their sale is prohibited to anyone under 18."