In this microbiological procedure, theoretically, the antibacterial or anti-fungal activity of the volatile oils from a chosen plant may be tested against a selection of gram-positive and gram-negative bacteria or a species of fungus. The growth of the bacteria or fungi are then monitored on a timely basis to measure the bacteriostatic or anti-fungal activity of the volatile oils. In some cases, a complete inhibition of growth for the bacteria tested can be observed.