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Canker Sores

Also indexed as: Aphthous Ulcers, Mouth Ulcers


Pain caused by canker sores can make it difficult to eat, drink, or speak. How can you soothe the pain and shorten the healing time? According to research or other evidence, the following self-care steps may be helpful:

What you need to know

  • Trade in your toothpaste
  • SLS (sodium lauryl sulfate) is a common toothpaste ingredient linked to canker sores; try an SLS-free toothpaste for three months
  • Aim for more balanced nutrition
  • Not getting the right amounts of certain vitamins can contribute to canker sores; take a multivitamin containing zinc and generous amounts of vitamin B-complex, and include iron if tests show that your levels are low
  • Try a little licorice
  • Try chewable (or powdered) deglycyrrhizinated licorice (DGL) to shorten canker sore healing time
  • Visit your dental care professional
  • Get checked for sources of minor trauma, such as rough fillings, braces, or poorly fitting dentures, which can aggravate canker sores
  • Forego certain foods
  • Work with a knowledgeable health professional to find out if you’re sensitive to foods that make symptoms worse

These recommendations are not comprehensive and are not intended to replace the advice of your doctor or pharmacist. Continue reading the full canker sores article for more in-depth, fully-referenced information on medicines, vitamins, herbs, and dietary and lifestyle changes that may be helpful.

About canker sores

Canker sores are small ulcerations within the mouth.

Doctors call this common condition aphthous stomatitis.

Product ratings for canker sores

Science Ratings Nutritional Supplements Herbs

B-complex (vitamin B1, vitamin B2, vitamin B6)

Folic acid (for deficiency only)

Iron (for iron deficiency only)

Lactobacillus acidophilus

Vitamin B12 (for deficiency only)

Zinc (for deficiency only)

Aloe vera

Licorice (DGL)











Witch hazel

See also:  Homeopathic Remedies for Canker Sores
3Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

What are the symptoms?

Canker sores appear alone or in clusters as shallow, painful erosions in the mucous membrane inside the mouth. They typically have slightly raised, yellowish borders surrounded by a red zone, and are sometimes covered with a yellowish opaque material. Fatigue, fever, and swollen lymph nodes may be present in severe attacks.

Medical options

Over-the-counter treatment consists of local anesthetics, such as benzocaine (Anbesol®, Maximum Strength Orajel®, Zilactin-B®), which provide pain relief, and antiseptics containing carbamide peroxide (Gly-Oxide Liquid®, Cankaid®, Orajel Perioseptic®).

Prescription drugs include antiseptic mouthwashes, such as chlorhexidine (Peridex®, Periogard®), and the oral anti-inflammatory products, amlexanox (Aphthasol®), triamcinolone (Kenalog in Orabase®), and hydrocortisone (Orabase-HCA®). Occasionally, an antibiotic mouth rinse containing tetracycline is prescribed for individuals with multiple sores.

Dietary changes that may be helpful

Sensitivity to gluten, a protein found in wheat and other grains, has been associated with recurrent canker sores in some people. In preliminary trials, avoidance of gluten has reduced recurrent canker sores in people whether or not they had celiac disease,1 2 3 but a double-blind trial did not find gluten avoidance helpful to people with recurrent canker sores who did not have celiac disease.4 One preliminary trial suggested that people with recurrent canker sores, whose blood contains antibodies to gliadin (a component of gluten), may respond to a gluten-free diet even if they have no evidence of the tissue changes associated with celiac disease.5

Other food sensitivities or allergies may also make canker sores worse.6 7 One preliminary trial found evidence of food allergy in half of a group of people with recurrent canker sores; avoidance of the offending foods resulted in improvement in almost all cases.8 While a double-blind study concluded that typical allergy mechanisms play only a minor role,9 people with recurrent canker sores should discuss the diagnosis and treatment of food sensitivities with a doctor. For some people, treating allergies may be a key component to restoring health.

Lifestyle changes that may be helpful

Minor trauma from poor-fitting dentures, rough fillings, or braces can aggravate canker sores and should be remedied by a dentist.

Several reports have found sodium lauryl sulfate (SLS), a component of some toothpastes, to be a potential cause of canker sores.10 In one trial, most recurrent canker sores were eliminated just by avoiding toothpaste containing SLS for three months.11 Positive effects of eliminating SLS have been confirmed in double-blind research.12 SLS is thought to increase the risk of canker sores by removing a protective coating (mucin) in the mouth. People with recurrent canker sores should use an SLS-free toothpaste for several months to see if such a change helps.

Measurements of stress were associated with recurrent canker sores in one preliminary study,13 but not in another.14 More research is needed to determine whether stress reduction techniques might reduce canker sore recurrences.

Vitamins that may be helpful

Several preliminary studies,15 16 17 18 though not all,19 have found a surprisingly high incidence of iron and B vitamin deficiency among people with recurrent canker sores. Treating these deficiencies has been reported in preliminary20 21 and controlled22 studies to reduce or eliminate recurrences in most cases. Supplementing daily with B vitamins—300 mg vitamin B1, 20 mg vitamin B2, and 150 mg vitamin B6—has been reported to provide some people with relief.23 Thiamine (B1) deficiency specifically has been linked to an increased risk of canker sores.24 The right supplemental level of iron requires diagnosis of an iron deficiency by a healthcare professional using lab tests.

Zinc deficiency has also been linked with recurrent canker sores in preliminary studies25 and in one case report.26 A preliminary trial found that supplementation with up to 150 mg of zinc per day reduced recurrences of canker sores by 50 to 100%; participants who were zinc deficient experienced the most consistent benefit.27 However, a double-blind trial (that did not test people for zinc deficiency) did not find zinc supplements helpful for recurrent canker sores.28

According to preliminary reports, some people with recurrent canker sores may respond to topical and/or oral use of Lactobacillus acidophilus29 and Lactobacillus bulgaricus.30 However, a double-blind study found no effect of acidophilus bacteria on the healing time of canker sores.31

Are there any side effects or interactions?
Refer to the individual supplement for information about any side effects or interactions.

Herbs that may be helpful

Licorice that has had the glycyrrhizic acid removed is called deglycyrrhizinated licorice (DGL). Glycyrrhizic acid is the portion of licorice root that can increase blood pressure and cause water retention in some people. The wound-healing and soothing components of the root remain in DGL.

A mixture of DGL and warm water applied to the inside of the mouth may shorten the healing time for canker sores, according to a double-blind trial.32 This DGL mixture is made by combining 200 mg of powdered DGL and 200 ml of warm water. It can then be swished in the mouth for two to three minutes, then spit out. This procedure may be repeated each morning and evening for one week. Chewable DGL tablets may be an acceptable substitute.

A gel containing the aloe polysaccharide acemannon was found in one double-blind trial to speed the healing of canker sores better than the conventional treatment Orabase Plain®.33 The gel was applied four times daily. Because acemannon levels can vary widely in commercial aloe gel products, it is difficult to translate these results to the use of aloe gel for canker sores.

The antiviral, immune-enhancing, and wound-healing properties of echinacea may make this herb a reasonable choice for canker sores. Liquid echinacea in the amount of 4 ml can be swished in the mouth for two to three minutes, then swallowed. This procedure may be repeated three times per day. However, no research has investigated the possible effects of this treatment.

Because of its soothing effect on mucous membranes (including the lining of the mouth) and its healing properties, chamomile may be tried for canker sores and other mouth irritations.34 A strong tea made from chamomile tincture can be swished in the mouth before swallowing, three to four times per day. Goldenseal has also been used historically as a mouthwash to help heal canker sores.

Myrrh, another traditional remedy with wound-healing properties, has a long history of use for mouth and gum irritations. Some herbalists suggest mixing 200 to 300 mg of herbal extract or 4 ml of myrrh tincture with warm water and swishing it in the mouth before swallowing; this can be done two to three times per day.

Historically, herbs known as astringents have been used to soothe the pain of canker sores. These herbs usually contain tannins that can bind up fluids and possibly relieve inflammation. They are used as a mouth rinse and then are spit out. None of these herbs has been studied in modern times. Examples of astringent herbs include agrimony, cranesbill, tormentil, oak, periwinkle, and witch hazel. Witch hazel is approved by the German Commission E for local inflammations of the mouth, presumably a condition that includes canker sores.

Are there any side effects or interactions?
Refer to the individual herb for information about any side effects or interactions.


1. Wray D. Gluten-sensitive recurrent aphthous stomatitis. Dig Dis Sci 1981;26:737–40.

2. Ferguson R, Basu MK, Asquith P, Cooke WT. Jejunal mucosal abnormalities in patients with recurrent aphthous ulceration. Br Med J 1976;1(6000):11–13.

3. Ferguson MM, Wray D, Carmichael HA, et al. Coeliac disease associated with recurrent aphthae. Gut 1980;21:223–6.

4. Hunter IP, Ferguson MM, Scully C, et al. Effects of dietary gluten elimination in patients with recurrent minor aphthous stomatitis and no detectable gluten enteropathy. Oral Surg Oral Med Oral Pathol 1993;75:595–8.

5. O’Farrelly C, O’Mahony C, Graeme-Cook F, et al. Gliadin antibodies identify gluten-sensitive oral ulceration in the absence of villous atrophy. J Oral Pathol Med 1991;20:476–8.

6. Hay KD, Reade PC. The use of an elimination diet in the treatment of recurrent aphthous ulceration of the oral cavity. Oral Surg Oral Med Oral Pathol 1984;57:504–7.

7. Wright A, Ryan FP, Willingham SE, et al. Food allergy or intolerance in severe recurrent aphthous ulceration of the mouth. BMJ 1986;292:1237.

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11. Herlosfson BB, Barkvoll P. Sodium lauryl sulfate and recurrent aphthous ulcers. A preliminary trial. Acta Odontol Scand 1994;52:257–9.

12. Herlosfson BB, Barkvoll P. The effect of two toothpaste detergents on the frequency of recurrent aphthous ulcers. Acta Odontol Scand 1996;54:150–3.

13. McCartan BE, Lamey PJ, Wallace AM. Salivary cortisol and anxiety in recurrent aphthous stomatitis. J Oral Pathol Med 1996;25:357–9.

14. Pedersen A. Psychologic stress and recurrent aphthous ulceration. J Oral Pathol Med 1989;18:119–22.

15. Porter SR, Scully C, Flint S. Hematologic status in recurrent aphthous stomatitis compared to other oral disease. Oral Surg Oral Med Oral Pathol 1988;66:41–4.

16. Palopoli J, Waxman J. Recurrent aphthous stomatitis and vitamin B12 deficiency. South Med J 1990;83:475–7.

17. Wray D, Ferguson MM, Hutcheon WA, Dagg JH. Nutritional deficiencies in recurrent aphthae. J Oral Pathol 1978;7:418–23.

18. Barnadas MA, Remacha A, Condomines J, de Moragas JM. [Hematologic deficiencies in patients with recurrent oral aphthae]. Med Clin (Barc) 1997;109:85–7 [in Spanish].

19. Olson JA, Feinberg I, Silverman S, et al. Serum vitamin B12, folate, and iron levels in recurrent aphthous ulceration. Oral Surg Oral Med Oral Pathol 1982;54:517–20.

20. Weusten BL, van de Wiel A. Aphthous ulcers and vitamin B12 deficiency. Neth J Med 1998;53:172–5.

21. Porter S, Flint S, Scully C, Keith O. Recurrent aphthous stomatitis: the efficacy of replacement therapy in patients with underlying hematinic deficiencies. Ann Dent 1992;51:14–6.

22. Wray D, Ferguson MM, Mason DK, et al. Recurrent aphthae: treatment with vitamin B12, folic acid, and iron. Br Med J 1975;2(5969):490–3.

23. Nolan A, McIntosh WB, Allam BF, Lamey PJ. Recurrent aphthous ulceration: vitamin B1, B2 and B6 status and response to replacement therapy. J Oral Pathol Med 1991;20:389–91.

24. Haisraeli-Shalish M, Livneh A, Katz J, et al. Recurrent aphthous stomatitis and thiamine deficiency. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996;82:634–6.

25. Pang JF. Relation between treatment with traditional Chinese medicine for recurrent aphthous ulcer and human zinc and copper. Zhongguo Zhong Xi Yi Jie He Za Zhi 1992;12:280–2, 260–1 [in Chinese].

26. Endre L. Recurrent aphthous ulceration with zinc deficiency and cellular immune deficiency. Oral Surg Oral Med Oral Pathol 1991;72:559–61.

27. Merchant HW, Gangarosa LP, Glassman AB, Sobel RE. Zinc sulfate supplementation for treatment of recurring oral ulcers. South Med J 1977;70:559–61.

28. Wray D. A double-blind trial of systemic zinc sulfate in recurrent aphthous stomatitis. Oral Surg Oral Med Oral Pathol 1982;53:469–72.

29. James APR. Common dermatologic disorders. CIBA Clin Symposia 1967;19:38–64.

30. Werbach MR. Nutritional Influences on Illness, 2d ed. Tarzana, CA: Third Line Press, 1993, 56 [review].

31. Gerenrich RL, Hart RW. Treatment of oral ulcerations with Bacid (Lactobacillus acidophilus). Oral Surg 1970;30:196–200.

32. Das SK, Gulati AK, Singh VP. Deglycyrrhizinated licorice in aphthous ulcers. J Assoc Physicians India 1989; 37:647.

33. Plemons JM, Reps TD, Binnie WH, et al. Evaluation of acemannan in the treatment of recurrent aphthous stomatitis. Wounds 1994;6:40–5.

34. Nasemann T. Kamillosan therapy in dermatology. Z Allgemeinmed 1975; 25:1105–6.

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