Canker sores are small ulcers in the mouth caused by an assortment of viruses. A susceptibility to canker sores tends to run in families. No successful conventional treatment is available.

Proposed Natural Treatments for Canker Sores

A highly preliminary study suggests that a chemically altered form of the herb licorice known as deglycyrrhizinated licorice (DGL) may be useful for speeding the resolution of canker sores. 1 However, because this study lacked a control group, its results are not reliable. (See Why Does This Database Rely on Double-blind Studies? ) Besides the absence of proof of its efficacy, DGL must be sucked to coat the canker sores, and some people find its taste objectionable.

A product containing vitamins and minerals as well as the herbs paprika, rosemary , peppermint , milfoil, hawthorn , and pumpkin seed has been used in Scandinavia for many years as a treatment for various mouth-related conditions. A small 6-month study reported that use of this product could reduce frequency of canker sores. 2 However, two subsequent studies failed to find any meaningful benefit. 3-4

One small double-blind study found benefits with an extract of the bark of the red mangrove tree, Rhizophora mangle . 5

A study performed in Iraq reported benefits through use of a mouthwash containing 5% lactic acid. 7

Other herbs and supplements sometimes recommended for canker sores but lacking supporting evidence include caraway , oak bark , witch hazel , acidophilus , calendula , slippery elm , and vitamin B 1 .

One study failed to find that alpha-linolenic acid from perilla oil reduced incidence of canker sores. 6