Six people are in a serious condition after taking part in a medical trial for an unnamed European laboratory to test a new drug, France's health ministry said.
The ministry did not say what the medicine was intended to be used for, but said the six volunteers, one of whom was in a coma, had been in good health until taking the oral medication at the clinic in Brittany, northern France.
French TV channel iTele said the trial was for a painkiller containing cannabis and took place at a laboratory in Rennes.
"This test was carried out at a private facility specialised in carrying out clinical trials," the ministry said in a statement.
All trials on the drug have now been suspended and all volunteers who have taken part in the trial are being called back.
