Ascidians exhibit pronounced pharmacological activities which may be of use in the biomedical area. In the present study methanolic extract of the simple ascidian, Phallusia nigra Sav. has been tested against eleven bacterial and three fungal pathogens (hospital isolates) by using disc diffusion method. The extract showed high degree of activity against all the tested bacterial isolates and fungal pathogens in increasing concentrations when compared to that of the standard drugs used. Methanol extract showed the maximum antimicrobial activity. Hence the Minimum Inhibitory Concentration (MIC) for the methanol extract was determined.
