Abbie Lee Everett posted the image of her nephew Ben, 14, on Facebook saying he was "lucky to be alive".
"It's not an easy photo to look at is it? He ended up in a coma because of somebody spiking his drink," she said.
North Wales Police is investigating an incident in Old Colwyn, Conwy county, on Saturday night.
Ms Everett said "people may not like this picture" but Ben, who is now home from hospital, had agreed for it to be shared to show what can happen.
She added that few people show the consequences of when "kids can get their hands on drugs".
"He ended up in a coma because of somebody spiking his drink.. he was lucky to be alive if another lad didn't carry him home when he did and my sister and her husband phoning an ambulance when they did, he wouldn't be here," she posted.
"His bloods came back as some alcohol in his blood but really high of MDMA. A dodgy drug nearly took his life, is it really worth taking these kind of drugs?"
She added: "Please share to show kids what can actually happen."
Police said no arrests have been made but appealed for information.
A photograph of a teenager lying in a coma after his drink was "spiked with ecstasy" has been shared by his family online to raise awareness of drugs.