A GP fighting a defamation lawsuit filed by a US-based naturopath, who claims he called her a fraud who exploited patients, will argue he was simply telling the truth.

Farrah Agustin-Smith is seeking over $1 million in damages from Dr Adam Smith for lost distributor deals and sales after he attempted to debunk claims that remedies she was selling online could cure cancer, diabetes and other serious medical conditions.

She has also claimed the Melbourne GP’s videos, which he posted on his YouTube channel, led to emotional stress that caused her to miscarry in May this year.

But in his amended defence, filed with the Supreme Court of Victoria last month, Dr Smith says he will argue she “is a fraud”, alleging she falsely claims to be a Harvard University–trained medical doctor.