A Quebec woman rushed to hospital after undergoing an overnight detoxification spa treatment involving intense sweating has died.

The woman, 35, died late Friday afternoon in a Drummondville hospital, said Quebec provincial police.

She and another woman were hospitalized after undergoing a detoxification treatment at the Reine de Paix farmhouse in Durham, a small town near Drummondville.

"The treatments consisted of a process of sweating by being all wrapped in plastic with mud, and also with blankets," said Sgt. Éloise Cossette. Both women were also encased in cardboard boxes.

They were both unconscious when emergency services arrived at the rented farmhouse early Friday morning.

The second woman regained consciousness during the ambulance ride to Sainte-Croix Hospital in Drummondville and is in stable condition.

At least 10 people were undergoing the detox treatments at the time, which lasted for several hours, and did not include drinking water.

Police are investigating the farmhouse, which is being rented by a woman who offers an initiation to Reiki, a practice developed by a Japanese Buddhist in the 1920s.

Neighbours have previously complained to police about the farmhouse, after hearing loud screaming on the property.

"The screaming was odd, it gave me shivers," said neighbour Roxanne Labonté, who called authorities a month ago to complain about noise from the farmhouse.