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 And, in a second, better designed trial employing a dissolving adhesive patch with glycyrrhiza root extract, researchers noted an improvement in ulcer size and pain compared to the use of a placebo patch.8

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 B1.

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