No, you should avoid eating bananas while taking Flagyl (metronidazole).
According to the provided reference, bananas should be avoided when taking Flagyl:
Alcohol (tap beer, sherry and red wine), avocados, salami, chocolate and bananas: Avoid drinking these beverages and eating these foods that have tyramine if you take drugs like linezolid (Zyvox) and metronidazole (Flagyl), which treat bacterial infections.
This is because bananas, along with other foods listed, contain tyramine, which can interact negatively with Flagyl.
