Candida albicans is a diploid fungus (a form of yeast) and a causal agent of opportunistic oral and genital infections in humans. C. albicans is commensal and is among the gut flora, the many organisms that live in the human mouth and gastrointestinal tract. Under normal circumstances, C. albicans lives in 80 % of the human population with no harmful effects, although overgrowth results in candidiasis. Description: Candida albicans.