Accused triple murderer Erin Patterson lied about throwing up remains from a beef Wellington and serving herself on a different plate, a prosecutor alleges.

On her sixth day in the witness box, the 50-year-old has disputed evidence from a doctor, nurse, her estranged husband Simon and what the only surviving lunch guest told the jury in her trial.

Patterson has entered week seven of a Victorian Supreme Court trial accused of three murders and one attempted murder over a toxic mushroom dish she served up to Simon’s family in July 2023.

Her former in-laws Don and Gail Patterson, 70, and Gail’s sister Heather Wilkinson, 66, all died in hospital days after eating death cap mushroom-laced beef Wellingtons cooked by Patterson.

She has pleaded not guilty to all charges and claims the poisonings were a terrible accident.

Patterson last week admitted foraging for wild mushrooms and accepted they may have been in the individual beef Wellingtons that she had prepared.

Crown prosecutor Nanette Rogers SC, at the beginning of her third day cross-examining Patterson on Tuesday, accused her of more lies.

On Friday, Patterson said she had a pre-surgery appointment for gastric bypass procedure at Enrich Clinic in Melbourne. But Rogers said that Enrich “does not offer gastric bypass or sleeve surgery”.

“I don’t know,” Patterson said.

“I had an appointment with them … It was for weight-loss surgery but maybe it was a different kind.”

When Rogers suggested she had lied about that appointment, Patterson said: “It wasn’t a lie, that’s what my memory was”.

Rogers quizzed Patterson about sole surviving lunch guest Ian Wilkinson’s evidence to the jury about being served the beef Wellington on one of four large grey plates.

He also told the jury, in week two of the trial, Patterson had served herself on a smaller orange or tan plate.

Patterson said she did not own any grey plates, and did not serve herself on a plate that was orange, tan and small.

Rogers asked Patterson about evidence that Heather Wilkinson said she noticed Patterson had served herself the food on a “coloured plate which was different from the rest”.

“I didn’t serve myself at all,” she said, before adding she wanted to “clarify” she did not own any matching sets of plates.

“Somebody would’ve had different plates and I don’t have four plates the same,” Patterson said.

Rogers suggested her “whole story is untrue” about plating the food, to which Patterson replied: “You’re wrong”.

Rogers suggested directly to Patterson that she lied to medical professionals about vomiting to “try to account for why you didn’t get seriously ill”.

“I wish that was true but it’s not,” Patterson said.

She further disputed evidence from Simon, saying she did not tell him she was worried she may “poo her pants” if she drove her son’s friend home after the lunch.

She disputed evidence from Leongatha doctor and nurse, Chris Webster and Kylie Ashton, about what they discussed when she admitted herself to hospital two days after the lunch.

She said Leongatha hospital staff would not tell her what had happened to the other lunch guests.

Patterson said she “probably was very stressed” when she went to the hospital because doctors had suspected death cap mushroom poisoning in the meal she prepared.

“I was anxious at the idea we might’ve eaten those things,” she said.

The trial continues.

-AAP