A 13-year-old boy is in a critical condition after taking an unknown drug.
Greater Manchester Police (GMP) believe he may have taken MDMA or ecstasy known as Magic.
The sick teenager, who is now in a critical but stable condition in hospital, was discovered after police were called to Timperley Metrolink station on Saturday at 4.30pm.
Inspector John Cave warned youngsters to "think twice" before taking unknown drugs as they could kill, saying "it's not worth the risk".
He said: "It is very early stages and we are still working to establish exactly what drug he has taken, however the boy is very poorly and we want to urge anyone who may have also taken the drug to get checked out at hospital as soon as possible.
"It is critical that young people understand the implications of taking drugs and would urge that they think twice before doing so. People taking these drugs don't know what they contain or the effect they will have - it's not worth the risk of ending up in hospital or even losing a life."
GMP urged anyone with information about this incident to call police on 101 or Crimestoppers on 0800 555 111.
People can also go online - to www.talktofrank.com or call Talk to Frank on 0800 777 6600 - for help or advice on all drugs.