Essential oils (EOs) are complex natural products of plant origin and exhibit different desirable, e.g., antimicrobial properties. Their growth inhibition effect on the pathogenic fungi of the genus, Fusarium, which forms deoxynivalenol (DON), has been documented. DON is the most common contaminant of grains and their products, causing strong emetic effects after their consumption. The aim of the study was to investigate the ability of selected EOs to degrade DON under in vitro conditions, using various incubation terms. The impact of a different temperature, pH, incubation time, mycotoxin, and essential oil concentration was tested. The results indicate that the kind of EO influences the effectiveness of mycotoxin level reduction, and the most effective EOs were palmarosa and lemon oils. A higher reduction of DON content by EOs was achieved after 24 h of the experiment (up to 72%), at a pH range between 3 and 6 and a temperature of 20 °C. Moreover, the effect of various doses of white and pink grapefruit and palmarosa EOs (100 and 200 μL/mL) on toxin level reduction was observed. The experiment confirmed that the selected EOs may be effective in DON reduction, as previously documented in experiments with zearalenone.