Squawvine (Mitchella repens) is a perennial herb native to North America and has a long history of use in traditional herbal medicine, particularly among Native American tribes and later by eclectic and physio-medical practitioners in the 19th and early 20th centuries. The plant is most commonly known for its use in supporting women's reproductive health, especially as a uterine tonic and for easing childbirth. However, squawvine has also been traditionally employed for its purported anti-inflammatory and astringent properties, which are believed to help in soothing various mucous membrane conditions, including mouth and throat irritations.

Historical herbal texts mention the use of squawvine as a mouthwash or gargle for sore mouths, ulcers, and "canker sores," though these references are generally anecdotal and lack rigorous clinical validation. The rationale for its use centers on its tannin content and mild astringency, which could theoretically reduce inflammation and promote healing of minor oral lesions. Nevertheless, there are no modern clinical trials or significant pharmacological studies that specifically validate squawvine’s effectiveness for canker sores. Thus, its use for this purpose is supported primarily by tradition and historical herbalist writings, rather than by contemporary scientific evidence.

In summary, while there is a traditional basis for using squawvine to support or treat canker sores, the quality and quantity of evidence are quite limited, and its efficacy for this condition has not been scientifically established.