In addition to improving organoleptic properties of food, herbs and spices are also an additional source of bioactive phytochemicals. Numerous studies confirm the connection between consumption of herbs and spices and a lower risk or mitigation of numerous diseases. This thesis assessed the intake of herbs and spices in omnivores and vegans and determined urinary levels of 8-hydroxydeoxyguanosine (8-OHdG), a marker of oxidative stress. The first morning urine samples were analyzed using an enzyme-linked immunosorbent assay (ELISA) and the obtained biomarker values were creatinine-corrected. Subjects filled out a survey with basic demographic and anthropometric data and a three-day food diary (two weekdays and one weekend day). Vegans consumed more herbs and spices (1.6 ± 4.3 g/day) than omnivores (1.4 ± 3.7 g/day) and had a significantly lower concentrations of 8-OHdG in urine (p = 0.031). Correlation analysis was used to examine the relationship between 8-OHdG levels and intakes of herbs and spices as well as macro- and micronutrients. The intakes of herbs and spices were not significantly associated with urinary 8-OHdG levels. Alcohol intake had the strongest positive correlation with 8-OHdG levels (r = 0.551; p = 0.011), while linoleic acid had the strongest negative correlation (r = -0.446; p = 0.048). Protein, saturated and monounsaturated fat intakes were positively correlated with 8-OHdG, and the opposite was found for carbohydrate and fiber intakes. The results point to the conclusion that a vegan diet, characterized by a higher intake of phytochemical sources, promotes a better defense against oxidative stress.