Due to its high content of phenols, thyme is a very powerful antimicrobial. It must be diluted for topical applications. In scores of studies, thyme oil has demonstrated an ability to kill or retard some of the worst bacteria, fungi and viruses. It is also a stimulant oil, which has been historically used for mental clarity, courage and focus. Aromatherapists also recommend this oil as a circulatory stimulant and as an aid to digestion.