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.
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
One study failed to find that alpha-linolenic acid from perilla oil reduced incidence of canker sores.6
1. Das SK, Das V, Gulati AK, et al. Deglycyrrhizinated liquorice in aphthous ulcers. J Assoc Physicians India. 1989;37:647.
2. Pedersen A, Hougen HP, Klausen B et al. LongoVital in the prevention of recurrent aphthous ulceration. J Oral Pathol Med. 1990;19:371-375.
3. Brateli J, Hakeberg M, Jontell M et al. The effect of LongoVital on recurrent aphthous stomatitis in a controlled clinical trial. Oral Health Prev Dent. 2005;3:3-8.
4. Kolseth I, Herlofson B, Pedersen A et al. Norwegian LongoVital and recurrent aphthous ulceration: a randomized, double-blind, placebo-controlled study. Oral Dis. 2005;11:374-378.
5. de Armas E, Sarracent Y, Marrero E et al. Efficacy of Rhizophora mangle aqueous bark extract (RMABE) in the treatment of aphthous ulcers: a pilot study. Curr Med Res Opin. 2005;21:1711-1715.
6. Hamazaki K, Itomura M, Hamazaki T et al. Effects of cooking plant oils on recurrent aphthous stomatitis: a randomized, placebo-controlled, double-blind trial. Nutrition. 2006 Feb 9. [Epub ahead of print]
7. Sharquie KE, Al-Tammimy SM, Al-Mashhadani S, et al. Lactic acid 5 percent mouthwash is an effective mode of therapy in treatment of recurrent aphthous ulcerations. Dermatol Online J. 2006;12:2.
8. Martin MD, Sherman J, van der Ven P, et al. A controlled trial of a dissolving oral patch concerning glycyrrhiza (licorice) herbal extract for the treatment of aphthous ulcers. Gen Dent. 2008;56:206-210;quiz 211-212, 224.
Last reviewed August 2013 by EBSCO CAM Review Board
Last Updated: 8/22/2013