A Sydney naturopath who instructed a breastfeeding mother to stick to a "raw food" diet to cure her son's eczema has admitted that her advice endangered the baby's life.

Marilyn Bodnar, 61, is accused of directing the mother, a midwife who cannot be named for legal reasons, to abandon other medical advice and adhere to a strict diet of raw vegetables, fruit and seeds.

Leppington naturopath Marilyn Bodnar has pleaded guilty to causing danger of death to a child with her diet advice. Credit:Google +

By the time the mother took the baby to hospital, he was limp, had sunken eyes and police believe he was just days from death.

According to court documents, Bodnar, from Leppington in Sydney's south-west, made the mother feel guilty for eating "rubbish" during her pregnancy and using steroid creams for the boy's eczema.