This term refers to the body-wide infestation of the fungal Candida cells. The initially healthy, round yeast cells found in the intestines change into fungal cells, most commonly as a result of antibiotic use. These mutated fungus cells then push through the wall of the large and small intestines, entering into the bloodstream. They then travel throughout the body and establish themselves in different tissues.

While antibiotics are the main cause of systemic Candidiasis, birth control pills, steroids, and sugar also help create an environment for the fungus to colonize and spread throughout the body.