Pseudomonas aeruginosa is a widespread opportunistic pathogen that causes fatal infections in immunocompromised patients. Infections with these bacteria represent a significant challenge for modern medicine due to the increasing frequency of multidrug-resistant strains that do not respond to existing antibiotic therapies. Targeting new virulence factors and bacterial intercellular communication as therapeutic targets is a key to improving treatment. Essential oils and their active ingredients have been shown to have antimicrobial effects with no resistance reported, but they have not been sufficiently studied. In this work, the effect of Calamintha officinalis Moench essential oil and pulegon separately, and in combination with tobramycin, on the growth of Pseudomonas aeruginosa PAO1 planktonic bacterial cells and the synthesis of pyocyanin pigment as an important virulence factor was investigated. The effect on planktonic growth was determined by measuring the optical density of the culture at 600 nm. The effect on pyocyanin synthesis was determined by measuring pyocyanin absorption and normalizing the value according to the number of bacterial cells. The results showed that the Calamintha officinalis Moench essential oil and pulegon at a concentration of 0,5 mg/mL effectively inhibited the growth of Pseudomonas aeruginosa PAO1 separately, but also sinergistically in combination with 0,5 mg/L tobramycin in. It has also been shown that, at the concentrations used, neither the Calamintha officinalis Moench essential oil nor pulegon have an inhibitory effect on pyocyanin synthesis. In combination with tobramycin both have an antagonistic effect on piocyanin production. This work contributes to a more comprehensive understanding of antimicrobial and anti QS effects of the essential oils and their constituents on Pseudomonas aeruginosa, with the aim of improving the therapeutic possibilities for treating these bacterial infections.