A "serious accident" during a trial in France of a cannabis-based painkiller has left one person brain-dead and five hospitalised, Health Minister Marisol Touraine said Friday.

She said the six had been taking part in a "trial of an oral medication being developed by a European laboratory" in Rennes, northwest France.

"A serious accident took place," the minister said, adding the study had been halted and all volunteers taking part recalled.

The Paris prosecutor's office said an investigation had been opened.

Source :AFP