The Brisbane manslaughter trail of former Bundaberg-based surgeon Jayant Patel has heard test results showed no evidence of a serious intestinal disease in a hospital patient who died soon after surgery.

Mervyn Morris, 75, died in June 2003, three weeks after Patel removed part of his colon in Bundaberg hospital.

The prosecution alleges Patel should not have performed the operation.

It also alleges Patel misdiagnosed Mr Morris as having diverticulitis, rather than radiation proctitis, often caused by prostate cancer treatment, which Mr Morris previously had.

A histopathology report was conducted after Mr Morris' operation, examining the colon tissue.

It was shown to the Supreme Court jury, with the report showing there was no evidence of diverticulitis or malignancy.