One man was seriously ill and five others in hospital after taking a hallucinogenic drug today.
Police received a report expressing concerns for the welfare of people in a house in Ripon Gardens in Jesmond, Newcastle, just after 3am.
Northumbria Police and paramedics attended and six men - all believed to be aged between 19 and 22 - were taken to hospital.
Some of them are thought to be students.
Police believed they took a hallucinogenic drug called 2CB thought to have been bought over the internet.
Chief Superintendent Gary Calvert said: "We were called to the address early this morning and six people have been taken to hospital, one is in a critical condition.
"We are carrying out extensive inquiries and are working with our partner agencies to find out what has happened and warn others of the dangers.
"Taking any illegal drug is dangerous and potentially life threatening. 2CB is an illegal hallucinogenic drug.
"If anyone has any of these in their possession we urge them not to take them and hand them in to the police.
"Anyone who may have taken the drug and feels unwell should seek medical attention immediately.
"Medical professionals in the area have been alerted and if anyone has any information regarding this they should contact police as soon as possible."
2CB often comes in purple capsules and is a hallucinogen related to ecstasy.
It is also sold as white powder or small pills.
It is an illegal class A drug and is particularly dangerous when mixed with other substances.
Anyone who needs emergency medical attention should call 999.