Suspended Chinese medicine practitioner Yun Sen Luo, 56 this month, has pleaded not guilty to unlawfully killing a 56-year-old mother on June 8, 2018.
The alleged victim, in Sydney visiting family, approached him about a skin condition on May 26.
After learning she had diabetes, he advised her against using her "Western-style" medications and prescribed her various herbal remedies, the woman's daughter told the Sydney District Court on Thursday.
The mother's condition deteriorated, appearing in a trance, vomiting regularly and needing help to get to the toilet by the 11th day.
The daughter testified having never seen her mother in such a state, leading her to ask Luo whether her mother's condition was serious.
He quickly replied that he'd previously treated other diabetic patients and was adopting the same methods, she said.
"He also said he had managed to treat other patients ... and 'your mum is not in that critical situation yet'," the daughter said.
"He said my mum's pulse is very good (and) my mum was at the stage of recovery, only she was recovering more slowly than usual as she'd had Western medication for too many years."
Luo disputes him ever being told of the mother's diabetes, saying the only medicine he was informed about was that for travel sickness.
His lawyer said it couldn't be proven beyond reasonable doubt that the omission of diabetic medicine was the main cause of death.
"My client was never treating her for diabetes, he didn't know she had diabetes and he didn't really know about her medical history at all," barrister Peter Skinner said on Thursday.
The Crown alleges that during the first consultation on May 26, Luo said the mother could eat whatever fruits she likes and claimed Western medications had caused toxins to form inside her body.
"(His) final direction, that she stop taking Western medication and start taking herbal medications prescribed by him, set in train a series of events that led to her death," crown prosecutor Emma Blizard said on Thursday.
Luo allegedly attempted to treat the mother with saffron, Korean ginseng and other herbal substances, the court has been told.
One treatment appeared to improve her condition, allowing the mother to eat without vomiting, the daughter said.
But eventually, her mother was placed in adult nappies and barely left her room.
About 3.30am on June 5, the concerned daughter messaged Luo via WeChat to report her mother was cold, her eyes were rolling back and "she can barely speak".
Luo recommended a five-ingredient grape juice.
Come June 8, her hands were hot, her feet cold and she couldn't be roused. Luo recommended jackfruit and durian.
She later entered cardiac arrest and died in hospital.
Had she been taken to hospital earlier, she very likely would have lived, the Crown said.
"It must have been obvious to the accused in his discussions with the family that he was being treated by them as a person with specialist knowledge and they were deferring (to him)," Ms Blizard said.
Mr Skinner says none of the WeChat messages mentions diabetes, consistent with his client's case that he never knew of the woman's condition.
The trial, before Judge John Pickering without a jury, resumes on Monday.
