Police in Cheshire have issued an urgent warning about using legal highs after a number of people were hospitalised.
In recent days police have responded to a number of incidents linked to the substance Vertex which has left people in need of urgent hospital treatment.
Symptoms include profuse sweating, racing heartbeat, extreme muscle tension, delirious ranting and a very high body temperature.
Lab tests on samples of Vertex have shown that it contains potentially lethal chemicals that pose a serious risk to health.
In particular, the results have revealed a chemical called AB-CHMINACA, a substance believed to be responsible for fatalities in Europe.
Cheshire Constabulary have said they are "extremely concerned" and are urging people who may have taken the substances to seek medical help immediately.
Assistant Chief Constable Mark Roberts said: “This has become an increasingly worrying trend that has seen us respond to a number of incidents in the county, particularly over recent days.
“In light of the laboratory analysis I would advise anyone supplying, using or considering using Vertex to stop immediately before it’s too late. If you have taken it, seek medical assistance now.”
Officers have spoken to a number of outlets known to supply Vertex and advised them to remove it from their shelves indefinitely.
Known users of the substance have also been advised of the significant health risks it poses.