The Nelson teenager who was granted special dispensation to use medical cannabis has died.

Alex Renton's family has posted on a Facebook page dedicated to his journey that he died surrounded by his family, listening to music and tummy full of his mum's food.

The family say they're very grateful for the support they've received.

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Alex had been in an induced coma in Wellington hospital for two months after a seizure, and has been receiving cannabis oil brought in from the U.S as treatment.

He had earlier appeared to be rallying from the treatment.

After the first dose of the oil, Alex's mother Rose Renton said her son was now able to move.

"He moves now, which he hadn't done any of that for two months, so he's close to the surface but he's certainly not conscious and awake," she said.

The news has caused an outpouring of sadness and support for the Renton family on social media.