Bacterial resistance to antibiotics has led to the search for new substances with bactericidal activity. Among them are some extracts of plant origin, such as some essential oils, which have shown a potent antimicrobial action. At present, the antimicrobial properties of the essential oil of Thymus vulgaris have been studied. It has been reported that T. vulgaris essential oil has shown high antibacterial activity against Salmonella enteritidis, S. choleraesuis, S. typhimurium, Vibrio cholerae, Proteus mirabilis, P. vulgaris, Pseudomonas aeruginosa, Staphylococcus aureus, S. epidermidis, Enterococcus faecalis, Bacillus cereus, Escherichia coli. In the present work, the effect of T. vulgaris essential oil on the viability of eukaryotic cells was studied.