Prosecutors in Michigan in the United States have charged the euthanasia advocate, the retired Doctor, Jack Kevorkian, with murder after watching video evidence of him giving a lethal injection to a terminally-ill patient.

Doctor Kervorkian, who says he's helped many more terminally-ill patients end their lives, was shown on an American television show at the weekend administering a lethal injection to a man dying of an incurable wasting disease.

The dead man Thomas Youk and his family said they agreed to the lethal injection, but prosecutors say consent is not a defence against the law.

Doctor Kervorkian has been acquitted in three previous trials in the United States involving five other deaths.