Pseudomonas aeruginosa is a ubiquitous gram-negative non-fermentative bacterial species that exhibits natural resistance to some antibiotics and antiseptics, in addition to having a high expression of virulence factors, being responsible for causing, mainly, opportunistic infections in the hospital environment. It affects the respiratory tract causing about 80% of hospital pneumonias, being able to reach skin, soft tissues, eyes, ears, bones and the urinary tract. The treatment of nosocomial infections caused by P. aeruginosa is based on several classes of drugs, such as: Cephalosporins, Carbapenems, Aminoglycosides, among others. However, studies point to the existence of multiresistant species, including reserve drugs, such as imipenem, thus generating a public health problem. In addition, this year the World Health Organization has released a list of ten challenging multi-resistant microorganisms that require new antibiotics, and secondly the species Pseudomonas aeruginosa carbapenem-resistant. Given this panorama of bacteria resistant to multiple commercially available antibiotics, it is necessary to study new compounds with antibacterial activity. As a possibility to combat bacterial infections, the action of a natural product, the positive enantiomer of 4,6,6-trimethylbicyclo [3.1.1] hept-3-ene, also known as (+) - α-pinene, before the Pseudomonas aeruginosa strain ATCC 27853, using methodologies standardized by the Manual Clinical and Laboratory Standards Institute. Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration, and Nature Classification of Compound Effect were determined according to CBM/MIC ratio. The (+) - α-pinene was dissolved in 1% Tween 80, 5% DMSO and distilled water. In broth microdilution, the MIC was determined for the P. aeruginosa strain, at a concentration of 40 μL/mL, being characterized as bacteriostatic and the concentration 4 times higher than MIC was demonstrated to be bactericidal. This experiment made it possible to observe the action of the phytoconstituent on the species of Pseudomonas aeruginosa, emphasizing the need for permanent studies to determine the mechanism of action and toxicity of (+) - a - pinene allowing its future use against opportunistic infections caused by Pseudomonas aeruginosa.