Myrtle (Myrtus communis) has been traditionally used in various cultures for its medicinal properties, including as an antimicrobial and anti-inflammatory agent. In recent years, scientific research has explored its potential application for oral health issues such as canker sores (aphthous stomatitis). Several clinical studies, primarily from Iran and neighboring countries, have evaluated the effects of myrtle-based gels or mouthwashes on canker sores. These studies generally report that topical application of myrtle extract can reduce pain, inflammation, and healing time when compared to placebo or standard treatments.

The proposed mechanisms for its efficacy include its anti-inflammatory and antimicrobial properties, possibly due to compounds such as tannins, flavonoids, and essential oils present in the plant. Randomized controlled trials have shown statistically significant improvements in ulcer size and pain scores in patients treated with myrtle preparations. However, most studies have small sample sizes and are not widely replicated outside of specific regions, so while the evidence is promising, it is not yet robust or widely validated in international guidelines.

In summary, myrtle has both a basis in traditional use and emerging scientific support for treating canker sores, with clinical trials indicating a moderate level of evidence for its effectiveness.