The use of the Matapalo tree (Ficus insipida or other Ficus species commonly referred to as "Matapalo") for canker sores (aphthous ulcers) is primarily rooted in traditional medicine, particularly in Central and South American indigenous practices. In folk medicine, various parts of the Matapalo tree, including the latex or sap, have been applied topically for treating oral sores, wounds, and inflammation. The rationale is typically based on the plant’s reported antimicrobial and anti-inflammatory properties as perceived by traditional healers rather than on controlled scientific studies.

Scientific validation is lacking: there are no published clinical trials or robust laboratory studies directly examining the efficacy or safety of Matapalo tree extracts for treating canker sores in humans. Only a few phytochemical analyses exist, indicating the presence of compounds such as flavonoids and triterpenoids with general anti-inflammatory or antimicrobial potential. However, these findings are preliminary, and no direct link to the treatment of aphthous ulcers has been established in the scientific literature.

In summary, while Matapalo tree preparations are used traditionally for oral sores, this use is not substantiated by modern scientific research, and the evidence supporting its effectiveness is weak and anecdotal.