Systemic candida can be very damaging where the candida invades other parts of the body, rather than the mucus membranes. I know a woman who had a brain lesion caused by candida. She cured her candida on the program after about 2-3 years and had another cat scan - viola, no brain lesion.
So systemic candida is far-reaching and can appear like other illnesses in the body, even when the source is candida. Even liver problems can be caused by candida, and malfunctioning of many other organs, i.e. the thyroid.