Authors emphasize the pathogenetic importance of fungous dimorphism and its consequence in the usefulness of antimycotic drugs. For the study of drugs' activity on C. albicans, two models for the evaluation on yeast or mycelial form were developed. The first model is of candida growth on an animal cell culture, where a good mycelial form develops during the first 24 hours: authors demonstrated a synergism of the amphotericin B-rifampin combination, which is less evident in the traditional in vitro tests, and some activity of tolcyclate. The second model is an intracutaneous injection in the guinea pig of C. albicans, which quickly develops in the mycelial form, infiltrating the skin layers. Some interesting differences were recorded, comparing amphotericin B and ketoconazole. Moreover the authors used a therapy test in mice, based mainly on examination of the kidney.