The video demonstrates a method to evaluate the viability of anaerobic oral bacteria using fluorescent dyes and flow cytometry. It begins with culturing bacteria in oxygen-free broth, followed by resuspending a single colony from a blood agar plate. After incubation and dilution, the culture is stained with membrane-permeable and impermeable dyes. Flow cytometry is then used to distinguish live cells, which fluoresce green, from dead cells, which fluoresce red.