Some research suggests that oregano oil may help inhibit the growth of certain bacteria associated with urinary tract infections, including Escherichia coli and Proteus vulgaris. Laboratory studies indicate these compounds may interfere with bacterial movement and growth, potentially reducing their ability to colonize the urinary tract. However, much of this evidence comes from laboratory or preliminary research, and more high-quality clinical trials in humans are still needed.
There is also limited evidence suggesting oregano oil may have activity against certain intestinal parasites under specific conditions. Some studies have explored its effects on microorganisms such as Blastocystis hominis, although experts caution that these findings should not be interpreted as proof that oregano oil can eliminate all parasitic infections.