a canker sore (aphthous ulcer)

Canker sores (aka aphthous ulcers) are one of life’s little mysteries. Experts estimate that roughly one out of five people put up with these painful mouth lesions. Some suffer more than others:

“My husband has canker sores in his mouth all the time. The specialists we have been to say it is not curable and he just has to live with them. We have tried many topical remedies plus some prescription drugs without benefit.
“He is not sleeping well because of the pain and desperately needs some relief. We enjoy reading the remedies you share and wonder if you might have some suggestions that could help us now.”

The cause of canker sores is unknown, though citrus fruits, trauma to the mouth and weakened immunity have been blamed for these painful mouth lesions. Some research suggests that nutritional deficiencies (B vitamins or iron) may be partially responsible.
Although they normally last about a week to 10 days, some people are plagued by these sores for much longer periods of time. The pain and irritation can be so severe that eating solid food can be almost impossible.
Some readers believe that a foaming agent (SLS or sodium lauryl sulfate) found in many toothpastes contributes to the problem:

“My sister and daughter suffered from severe canker sores for years. My sister’s doctor told her to stop using toothpaste with SLS. Now, both my daughter and sister have very few outbreaks.”

Despite such a testimonial, research is equivocal regarding the benefits of using SLS-free toothpaste (Oral Diseases, Jan. 1999). Others are convinced that sugar is the culprit and cutting back on cookies and candy is the answer. Some readers believe nuts trigger an attack:

“I also suffered from massive canker sores. I finally realized that five days after eating walnuts the cankers would appear. Now I never touch the nuts and no sores!”

Many people believe the solution lies in the amino acid supplement L-lysine despite a lack of scientific evidence:

“I had troubles for years with canker sores. A friend told me to start talking L-lysine twice a day at the first sign of a canker sore. It stops canker sores from getting larger and heals them within a day or two.”

Although these home remedies have not been tested, some people report success with swishing their mouths with an ounce of sauerkraut juice in the morning and evening, then swallowing about a tablespoonful:

“It is an unusual cure for canker sores, but I had a recurring sore that went away overnight after the first use of sauerkraut juice. And, you can have wieners and kraut with the leftovers.”

Another option is buttermilk:

“My oldest son used to get canker sores a lot. My mother-in-law gave us the ultimate cure that worked overnight. Swish cultured buttermilk in the mouth and hold it for about a minute then spit it out. We don’t know why it works, but it does.”

We have even heard that kiwi fruit helps:

“My husband got a canker sore on Thursday and we bought a few kiwis to try this cure. He ate one kiwi in the morning, and by the mid-afternoon the sore was dried up. A second kiwi wasn’t needed. Amazing.”

Since there is no standard medical cure for canker sores, trying an inexpensive home remedy may be worth considering.

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  1. Mary Ann
    Charlottesville VA

    Lysine is in crushed pineapple which may also help with canker sores

  2. Tom
    Sturgeon Bay, WI

    I also have suffered with canker sores my whole life – I am 60. Yes, I agree with many of the previous posts – avoid citrus fruits as well as acidic foods like tomatoes, and the SLS in toothpaste is a MAJOR factor. So up until the last year I have had the canker sores under control. This last year my immune system seemed to be weakened by strenuous training for doing triathlons. With that I would get canker sores as well as a sore throat. Now I can virtually trigger an attack by even moderate physical exercise. I have tried everything to build up my immune system to no avail. One thing I have found is Colloidal Silver spray seems to be effective in arresting and healing the canker sores, as well as helping the sore throat.

  3. Abigail

    When i was younger i used to get canker sores quite a lot and they would stay for about a week to ten days. Then my aunt told me this great trick that works overnight. Take a Q-Tip or your finger and dip it in yellow mustard and apply it to your canker sore and leave it on overnight and when you wake up its gone.

  4. Savannah

    It hurts so

  5. Kae

    In desperation I decided to try coconut oil. Oh my gosh, it worked! I used just regular coconut oil from the grocery. Actually coconut oil is a solid that melts in your mouth. I put a scraped-with-aQ-tip amount in my mouth. I let it melt, and the pain left. I was able to eat pizza without pain.

    I put another dose in my mouth at bedtime and slept through the night. I applied it in the morning and was pain-free all day. You can swallow it, since it is a food. Please try this. It worked for me. The canker sore looks like it is healing. I am so pleased.

  6. Cody
    Cody, Wy

    I work in the Emergency Department in the Hospital and just was talking to a co- worker about Canker Sores and she said when she was about twenty years old she seen a doctor for them and he treated her for small pox and she has never had a canker sore again. Makes sense.

  7. Wendy Guilette
    United States

    I was getting canker sores all the time. I heard about sls in toothpaste so I switched to Therabreath and I stopped getting them. I only got 1 canker sore in about a month but now I started getting them again. I haven’t changed anything. Does anyone have any suggestions?

    • Bill

      I get them from any plastic bottle i drink out of, so i only use glass

  8. Dave

    I’ve struggled with canker sores for about 8 years. Usually always have 1-2 in my mouth. Started taking D3 and haven’t had any in a month and a half. And there was a week in there where I bit my lip about 5 times which usually always brings one on, I did not get one this time.

  9. A.D.

    I’ll not comment on treatment but mostly on causes.
    I have noticed that canker sores will appear in my mouth:
    1) after using not too clean spoons/forks (re-using plastic spoons, knifes etc), drinking and re-using plastic bottles for water etc. I guess bacteria is the reason here .
    2) after major stress event
    3) eating acidic foods (pineapples)
    Currently I have a very bad, swollen, and painful canker sore on my tongue… it is hard to talk and eat. I read all of your comments and after work I am rushing to a store to buy some remedies and start treatment asap. I feel miserable.

    • Cody

      Whats D3

  10. AB

    I have had bad sores for years mostly from cuts i.e eating chips or bites on the tongue and cheek
    I use a bit of 5% iodine and dip it with my finger on the area were I expect or feel a sore developing
    I keep a little bottle of iodine with me and if if treated right away a few times a day the canker sore never develops !!!!
    Prevention is it!!!!

  11. D.p.

    My sores are from chemo and developed within three days of the first infusion. I have round two tomorrow and the first ones are not all gone yet. I am terrified that they will be back. Anyone have this problem?


    I only got canker sores after having too many English walnuts, but lately, I over-indulged in raw pecans and have one on my tongue. What works for me is moistening a styptic pencil (the kind used for cuts while shaving) and dabbing it a couple times on the spot, then wait a few minutes before I rinse out. Hope this helps someone.

  13. Dana

    Ever since I was a young child (age 7+) I have often times developed very painful canker sores after eating or drinking very acidic/citrus products. The best cure I eventually discovered and now always use is baking powder. I wet a cue tip with water and then dip it in baking powder. I hold the baking powder covered cue tip on my sore for about 15seconds & then rinse & repeat once. It does burn but it works great! Typically this treatment once or twice & the sore is gone.

  14. KHS

    I have come to the conclusion (after many years) that canker sores may be a symptom caused by different agents in different individuals. In my case, I have identified two factors (there may be more) that definitely provoke canker sores in *me*: (a) taking Vitamin C, and (b) eating significant quantities of acidic fruit or vegetables. For completely other reasons, I began using traditional Listerine-like mouthwash at least once a day quite a number of months ago. Combined with not taking Vit C (this means no multivitamins) and not eating acidic fruits and vegetables, I have not had any canker sores in quite some time.
    I am, however, knocking on wood because I can’t be sure that I have correctly identified all factors.

  15. CO

    I was just diagnosed with CLL last month. I have had chronic canker sores for years. What is this acid that you use and how can I find it?

  16. ps

    I had canker sores so bad, I even went to the dentist to get laser treatments, I tried everything I could read about, and nothing helped. I finally realized that every time I would eat anything with vinegar I would get the sores, I had been eating a lot of salads with vinegar and oil dressing. Now even if I have too much mustard I will get the canker sores back. I love vinegar and oil dressing I just wish I could find a cure for food allergies but at least I finally found out what was causing the sores. No more sores as long as I stay away from anything with vinegar!

  17. Tawana

    My son was 5yrs old when he started to get canker sores in his mouth. He would get 4 or 5 at one time. It became a nightmare. I spent more money on oral gel than I did when he was a baby. Using oral gel was the only way he could get through school. At one point his mouth broke out so bad with sores, he ended up being out of school for a week. The doctors here was no help. I finally found wheatgrass powder. I was actually looking for something for my husband to take and decided to give my boy some as well. He’s 8 now and so far he hasn’t had any in a few months. (knock on something! lol) Now my whole family is on the powdered wheatgrass. I do know taking higher mg’s of Vitamin C helps prevent them as well.

  18. Julie713

    Can you please give a few more details more about Salzer’s Solution? I can find no references to this solution on the internet.

  19. dlo

    I am 60 year old male and have suffered mouth ulcers since I was a teenager. In recent years, some of the outbreaks have been over multiple areas of my mouth and sometimes includes my tongue. I have used a number of home remedies and have not had much success.
    When I tried Alum, it hurt like crazy on application, but provided no apparent relief or healing. I have ground up aspirin and applied directly on the ulcer. It also hurt like crazy on application, but provided moderate relief, but did not seem to provide any speeding up of healing of the ulcer.
    I have also tried the sauerkraut juice. It provided almost immediate relief of the pain, but did not speed any healing. In fact, the next day, the ulcer was worse and my lip was swollen. I have also tried a prescription product, called Aphthasol, which provided no relief or apparent healing.
    Locally, one of our pharmacies mixes a solution called “Salzer’s Solution”, which requires a doctor’s prescription. You swish it in your mouth four times a day. I had one of my worse outbreaks two years ago…. It was so bad, all I could do was eat Jello and drink soup (delicately). I had to cancel many appointments I had for a couple of days because it hurt to even talk.
    My family doctor prescribed “Salzer’s Solution”. I was very skeptical, but the first application created a soothing sensation on the ulcers. Within 24 hours, I could eat whole food and within 48 hours, the ulcers were gone. I don’t know what is in the solution, but I have continued to use it anytime I get a mouth ulcer. It has always been effective at providing immediate relief and clearing up the ulcers in 24 to 48 hours.

  20. Lynn

    I am a female now 63 yrs old. Since I was about 13 I had canker sores inside my mouth which would become so severe they would split the sides of my tongue open. I couldn’t talk or eat. A few years ago, when they were really bad, I got desperate and figured I’d rinse my mouth with an antibiotic. All I had was Listerine. I tipped the bottle up and sloshed some into my mouth and almost fell over from the pain, but I steeled myself and kept it up.
    I repeated it a few more times.You may not believe this, but over the next few days they all healed. After that, as soon as I felt one coming on, I’d wash it with the Listerine, really sloshing it around like before, and within hours it is GONE. It never even gets to the point of a full canker sore, let alone dozens like I had my whole life. The pain of the Listerine on them is indescribable, but it is worth it. The incidents became fewer and fewer, and now it’s been several years since I’ve had one.

  21. LGF

    I am a dental hygienist. Everyone is different as far as what toothpaste bothers them. When I was in college, we were told Colgate was a brand that seemed to bother a lot of people as far as ulcers, sensitive teeth, etc. (myself included-I can’t use any form of Colgate–it hurts my teeth!) But I am surprised at the number of patients who I thought would be affected by certain brands, and do just fine. So I try trial and error to get desired results–and I always start with “plain” brands first, like “plain” Crest. In other words, no tartar-control or whitening types. Then we start with brands containing no sodium lauryl sulfate, like Biotene. I’m glad this person found what worked for them!

  22. HGHD

    I suffered from ulcers for years and read one time that tooth paste could cause these painful sores. I changed my tooth paste and have not had one since. I have used Pepsodent and Colgate without any problems. It is wonderful to have a comfortable mouth now. I would urge all who suffer to try this. My dentist had the same cure.

  23. BD

    I have been successful in controlling canker sores by taking alpha lipoic acid regularly. I agree that nuts can cause them. I also believe chocolate and the like can. I agree that canker sores imply a weakened immune system. In my case, when I have a canker sore, I feel fatigued, but I do not know which causes which.
    After many years of having canker sores, which began getting worse and becoming more associated with fatigue, I was finally diagnosed with chronic lymphocytic leukemia, so one wonders if there might be an association. By the way, I am the only person I know that uses alpha lipoic acid to control canker sores. I tried lysine but got no results.

  24. Grami

    I have had problems with my mouth since I took interferon in 1996. There seemed no relief. In addition, I have dry mouth. I was told by my dental hygienist to buy solid virgin coconut oil and put a teaspoon in my mouth. Wait till it melts and then swish for as long as you like. Expectorate. It won’t hurt you if you swallow it, it’s food. Also highly recommended is Seabuckthorn Fruit oil. Apply with a q-tip. You can get both at natural food stores or on-line.

  25. Richard

    I switched to SLS free about two years ago, and noticed a significant reduction in the number of canker sores. I would get them all the time but especially when I ate walnuts, citrus fruit, bananas and sour candy.

  26. Barbara Jean

    I have suffered with canker sores since I was 15,I am now 71. That is a long time to suffer. I read about toothpaste with SLS, I have used Crest since I was a teenager. I changed to a tooth paste without SLS about 3 weeks ago, I haven’t had a canker sore since. I normally would have 2 or 3 canker sores all of the time. It’s been a wonderful discovery for me. Many thanks, Barbara

  27. Carol B.

    I was very interested in the article post in the Cape Gazette. I had mouth ulcers all my life. Tried so-o-o-o many remedies. Then my dental hygienist suggested all natural toothpaste because of the SLS (sodium laurel sulfate) in regular toothpaste. I tried it and boy now I have a new lease on life. I have since gotten away from the toothpaste and now use Listerine Whitening mouthwash. It foams up in your mouth while you are brushing and it whitens your teeth as you do. It feels so GOOD to eat anything without the tears running down my face from the burning and hurt.

  28. karen

    I have found that a fairly new product, CankerMelts (produced by ORAHEALTH), works well for my canker sores. The primary active ingredient is glycyrrhiza extract (licorice root). They come as hard discs that ‘melt’ and adhere to the part of the mouth where you place them. I discovered them through my dentist, who gave me a sample. After seeing how successful they were, I discovered that none of the drugstores near my house carried them. However, they were easy to find and order online.

  29. RSH

    The most effective remedy for aphthous ulcers I have found is to crush two Lysine 500mg tablets and mix with 1/2 teaspoon Vaseline (petroleum jelly.) Apply directly to ulcers and leave overnight. Gone the next morning.

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