The prosecution has opened its case in the Brisbane manslaughter trial of former Bundaberg surgeon Jayant Patel.

Patel is accused of unlawfully causing the death of Mervyn Morris.

The 75-year-old pensioner died soon after Patel removed part of his colon in 2003.

Peter Davis SC for the Crown told the jury that Patel was charged with manslaughter and not murder because the Crown does not allege Patel intended to cause Mr Morris's death.

But he says Patel is accused of negligently providing medical treatment to Mr Morris.

He says it was that negligence that caused his death and Patel was therefore guilty of manslaughter.

Earlier, Supreme Court Judge George Fryberg told the jury members not to conduct their own investigations of the case against Patel.