Betulinic acid is a naturally occurring pentacyclic triterpenoid found in the bark of several plant species, particularly birch trees (Betula species). Scientific research over the past two decades has revealed that betulinic acid exhibits multiple biological activities, including notable antibacterial effects. In vitro studies have shown that betulinic acid can inhibit the growth of both Gram-positive and Gram-negative bacteria, such as Staphylococcus aureus (including some methicillin-resistant strains, MRSA), Escherichia coli, and Pseudomonas aeruginosa. The proposed mechanisms include disruption of bacterial membrane integrity and interference with protein synthesis or biofilm formation.

Despite these promising laboratory findings, there is limited evidence from animal studies and no robust clinical trials in humans directly supporting betulinic acid as a standalone or adjunctive therapy for bacterial infections. Its poor water solubility and bioavailability are notable challenges to its therapeutic application. Therefore, while there is scientific interest and preliminary validation for its antibacterial properties, betulinic acid is not yet recognized as an established alternative or support to conventional antibiotics in clinical practice. The current level of evidence is best characterized as preclinical, warranting further investigation before clinical recommendations can be made.