The Supreme Court in Brisbane has been told the Jayant Patel case has made many doctors anxious about performing risky procedures.
Patel, 62, has pleaded not guilty to unlawfully killing pensioner Mervyn Morris, who died three weeks after Patel removed his sigmoid colon in the Bundaberg Hospital in 2003.
The court has heard there was a previous trial.
Gastroenterologist Johan van den Bogaerde has been cross-examined in the witness box by the Crown.
He says the previous trial was very important in the medical fraternity.
Dr van den Bogaerde told the court the work performed by doctors is extremely risky and that, unfortunately, people sometimes die.
He said the case had made him extremely worried about performing endoscopies on patients and that this feeling was shared by many doctors, whether they were overseas-trained or not.
Meanwhile, a third doctor has given evidence in support of Patel's diagnosis of Mr Morris.
Nambour Hospital's director of surgery, Ratna Aseervatham, reviewed Mr Morris's medical records.
He told the court the top of his list of possible diagnoses was diverticular bleeding, in line with Patel's conclusion.
Dr Aseervatham said the decision to operate is a balancing act between benefit and risk and comes down to a doctor's call.
Under cross examination, he agreed there were alternatives at the time, including transfusing Mr Morris and sending him home to be monitored.