An inquiry has been launched to find a drug dealer after four people were taken ill during the early hours of today.
Officers were first called to St James Boulevard in Newcastle city centre just after midnight after receiving reports of concern for the welfare of a 21-year-old man and an 18-year-old woman.
The woman's condition is described as potentially life-threatening but she has been stabilised by doctors.
The man was checked over by medical staff but has since been discharged.
Around an hour later police received another call to the city centre after reports of concern for the welfare of a man and a woman, both aged 18.
Both were taken to hospital by paramedics but their condition is not described as life threatening and they remain at hospital for observation.
A quantity of the drugs, believed to be ecstasy, has been seized by police and an investigation is underway to identify the person who has supplied the drugs.
Police are now appealing for anyone with information to come forward but they have also issued a warning around the dangers of taking illegal drugs.
Detective Inspector Sally MacDonald said: "Taking illegal drugs is incredibly dangerous and the fact four people have been taken ill in just one evening is particularly worrying.
"We want to alert people across the North East of the dangers of taking illegal substances, or drugs that have not been prescribed to them, as the consequences could prove to be fatal.
"If anyone has taken an illegal substance and becomes unwell then they should seek immediate medical advice but we would implore people to stay safe.
"An investigation is underway to establish who has supplied the drugs on this occasion and anyone with information about these ecstasy pills is encouraged to contact police."
To report information about drugs and drugs supply contact Northumbria Police on 101, quoting reference 11 of 03/06/17 or Crimestoppers anonymously on 0800 555 111.
Anyone who needs emergency medical attention should call 999.