It was shown that polyenic antibiotics and their combinations with some other antifungal and antibacterial agents prevented transformation of the C. albicans yeast phase into the tissue one. Moreover, the fungus tissue form proved to be more sensitive than the yeast form to the drugs and especially to their combinations. The in vitro findings were confirmed by the in vivo studies. Combinations of amphotericin B with methacycline, rifampicin, 5-fluorocytosine or polymyxin B were more efficient than the polyene alone. Summation of the drug antifungal effects provided a 4-fold decrease in the polyene quantity required for administration to experimental animals.