The antifungal activity of the essential oils against the three fungi strains examined was assessed by the percentage of the inhibition rate (IR%) and minimum inhibitory concentration (MIC). In order to evaluate the quantity of essential oils needed to be used, a preliminary investigation was carried out with a volume of 10 µL and 20 µL of each of them. After this screening, the maximum concentration used was 60 µL, while the minimum volume used was 2.5 µL. The results presented in Figure 5, Figure 6 and Figure 7 for the antifungal activity of the essential oils tested are the ones from the 7th day of analyses. From all tested oils, the most effective were the essential oils of clove, thyme, and tea tree. The efficacy of these essential oils can be attributed to the terpenes and phenylpropanoides present in their composition. The research studies demonstrated that phenolic compounds are responsible for the antifungal potential of these oils.