The effect of amphotericin B combined with rifampicin or doxycycline on growth, oxygen consumption and ATP levels in cultures of Candida albicans, was studied. Alone, neither rifampicin nor doxycycline-even at high concentrations-affected the growth of the test organism. However, when combined with a concentration of amphotericin B which alone did not affect the growth of C. albicans, a pronoinced fungistatic effect was obtained with therapeutically attainable concentrations of the drugs.