This study was conducted in the laboratory of the Faculty of Science, University of Zawiya to find out the extent of the effect of the leaves of the alcoholic peppermint plant on the growth of the fungus (Aspergillus niger) isolated from the Microbiology Laboratory at Sabratah Oncology Hospital. This study showed that all the treatments of the plant extract of peppermint and in different concentrations (100mg\ ml.50mg\ml.25mg\ml) and anti-flenzol, where each of them was given an inhibition zone on the growth of the fungus (Aspergillus niger) on the nutritional medium (BAB) if the inhibition zone ranged from 2.2cm at a concentration of 100mg/ml and 1.9cm at a concentration of 50mg/ml and 1.4cm at a concentration of 25mg/ml and 0.2cm in the anti-flenzol, and it is clear from here that the effects of the plant extract inhibiting the growth of the fungus escalated with the increase in concentrations,and that the effect of the extract in in inhibiting the growth of the fungus, because the mint contains effective anti-fungal substances (Aspergillusniger)............... Keywords:.........Aspergillus niger, Plant Extracts, Antiflenzol, Gintamycin. Sabratha Oncology Hospital