Three 12-year-old girls rushed to hospital after taking ecstasy pills are now in a stable condition, police said.
The teenagers took so-called Teddy Tablets in Salford on Saturday and emergency services were called at around 9.50pm.
A man and a woman were arrested on suspicion of being in possession of drugs and are being held for questioning, Greater Manchester Police said.
They warn young people to stay away from the party drug - which has already led to the death of a 22-year-old woman in recent weeks and a 17-year-old girl a few months ago.
Anyone in possession of illegal substances was also urged to hand them into the police, chemists or medical practitioners.
Detective Chief Inspector Chris Walker said: "Sadly, three more young people, who are only 12 years old, have taken ecstasy and ended up in hospital.
"The girls took a type of ecstasy described as Teddy Tablets. It is imperative young people understand the implications and avoid taking drugs, to stop any more young people ending up in hospital.
"We will continue to repeat our warnings in the hope that young people will think twice before taking drugs, after seeing the damage they cause to lives. People taking these drugs don't know what they contain or what effect they will have. It's not worth the risk of ending up in hospital or even suffering fatal consequences."
Anyone with information about where this drug may have come from is asked to contact police on 101 as soon as possible, or the independent charity Crimestoppers on 0800 555 111.