Paramedics attended Saint Stephen’s College at Upper Coomera about 12.50pm after six 15-year-olds and one 14-year-old were falling in and out of consciousness after a suspected drug overdose.

They were taken to the Gold Coast University Hospital, where four remained in a critical condition, one in a serious condition, and two stable on Wednesday evening.

A Queensland Police Service spokesman said several mobile phones and electronic devices had been seized as part of the investigation and two crime scenes had been set up on the school grounds.

Queensland Ambulance Service senior operations supervisor Patrick Berry said they believed the students had swallowed a drug and were treating them for an overdose.

"These boys started to become very … not aware of their surroundings, one was having with his consciousness, others were feeling nauseous," he said.

"We would like to take the message home that any drugs at all are a danger to take.

"It's just Russian roulette, there is no such thing as recreational drugs."

Conflicting reports emerged on Wednesday about what drug the students had taken, but the police spokesman said it was too early to say and would be a matter of waiting for the toxicology results.

"The Queensland Police Service would like to remind the public that all illicit drugs are dangerous regardless of how they are sold or what you’ve been told," police said.

The toxicology results were expected to be returned on Thursday.

The school’s principal Jamie Dorrington posted to the school's Facebook page on Wednesday afternoon, informing parents of the incident.

"It is likely the students have ingested some kind of substance. While this is obviously of concern to me, it does allow me to reassure you that their illness was not due to anything contagious," the post said.

School mother Kristy Howard commented on the post, saying she was praying for the families of the boys.

"Hoping they make a full recovery. So very sad for our lovely school," she said.

Mother Karen Soeters said she felt sick when she arrived at the school and saw police and ambulances.

“Can’t we just wrap our babies in cotton wool and protect them from this crap,” she said.

The school put a stop to parents and members of the community commenting on its Facebook post about 7pm Wednesday when it turned off public comments.

Detectives from Gold Coast Child Protection and Investigation Unit are investigating.