Paramedics were called to St Stephen's College in Upper Coomera on Wednesday when the boys, aged 15 and 14, appeared to be under the influence of drugs.
Four boys were taken to Gold Coast University Hospital in a critical condition, with another boy transported in a serious condition.
The other two boys were stable when they were taken to hospital, with one student since released.
In a statement, the hospital said the conditions of all the students were improving.
Police are still awaiting the results of toxicology reports to confirm which drug was involved. There are reports it was the Russian designer anxiety drug Phenibut and may have been bought online.
Detective Senior Sergeant Greg Aubort says police need to ensure they can account for all the drugs involved.
"We certainly do need to be sure that we can account for all of the drugs that were involved," he said.
"So if there is any information out there from any person at all, be that a student or family, who has any information about the existence of more of this drug or its uses elsewhere, we'd appreciate that information to come to us."
Police are working with other agencies such as the Australian Border Force to substantiate how the boys obtained the drugs.
The incident has shocked the school's community, with parents of other students concerned for their children's safety.
"I'd have to seriously consider if I leave my children at the school, to be honest," parent Greg Peters told ABC radio on Thursday morning.
"This is fairly serious, you would think when seven boys are silly enough to want to attempt that at school it's not good."
Opposition leader Bill Shorten said the incident was every teenage parent's worst "nightmare".
"I think it's shocking, I've got teenage kids. I just hope the kids get better.
I cannot imagine what their parents are going through," Mr Shorten told ABC radio.
"If kids are able to buy serious drugs online then we have to do everything we can to stop that."
