A Montreal naturopath is on trial facing criminal charges in connection to the 2008 death of an elderly man in her care.

Mitra Javanmardi faces charges of involuntary manslaughter and criminal negligence causing death, after injecting Roger Matern with magnesium.

Matern, 84, was suffering from breathing problems because of fluid in his lungs following heart surgery.

On Thursday, his widow Denise Matern testified her husband was being cared for by a cardiologist, but they decided to consult alternative medicine as a complement to his care.

A friend recommended Javanmardi.

Matern told the court the couple knew the naturopath sometimes injected her patients, and trusted her care.

They provided her with a list of drugs the elderly man was taking, before he received his magnesium injection.

Matern testified her husband became disoriented, had trouble walking and couldn't speak after the injection.

He was rushed to the hospital in the middle of the night and died the next day.

Javanmardi had assured the couple there was no danger with the injection, Matern said.

Under Quebec health law, naturopaths are not authorized to administer drugs intravenously.

The trial continues later this month.