Canker Sore FAQs
Questions about canker sores? You’re not alone. Keep reading for answers to the most frequently asked questions about canker sores and canker sore treatment and identification.
Check out this article for a full breakdown of what canker sores are and how they’re treated.
Q: Is there a cure for canker sores?
Not exactly. People who get canker sores tend to get them over and over again. However, treatments like light therapy are reducing pain and healing times for canker sores so people can live more comfortably with canker sores.
Q: Can anything prevent canker sores?
There is no known or proven canker sore preventative treatment, but if you keep a record of when you get canker sores you may notice correlations with other events in your life, like stress, diet, hormonal changes, etc.
Q: How long do canker sores last?
Most canker sores last about a week, but more severe cases can last 2+ weeks. In clinical studies, light therapy treatments have reduced the healing time for canker sores to a matter of days. [7,12]
Q: Are canker sores contagious?
No. Unlike cold sores, canker sores are not contagious and aren’t caused by an underlying virus. They cannot be transmitted or spread, even if you have open sores.
Q: Can you spread canker sores from kissing?
No, canker sores can’t be spread from kissing or oral contact.
Q: Is a canker sore herpes?
No. A canker sore is not caused by a virus like cold sores and herpes.
Q: Can you use baking soda or salt water for canker sores?
Baking soda is one of many home remedies used to ease the pain of canker sores. Like honey or cloves or salt water, some say it works for their canker sores, but baking soda hasn’t been tested and proven in clinical trials.
Q: Are there antibiotics for canker sores?
In more severe cases, antibacterial mouthwashes and/or corticosteroid ointments may be prescribed to reduce pain and irritation. Acyclovir is an antiviral drug that is sometimes prescribed in severe canker sore cases.
Q: Do canker sores occur on tonsils? Canker sore or strep throat?
Canker sores can occur on the tonsils and cause a sore throat that may seem like strep throat or tonsillitis, but these conditions are not related.
Q: Are there any new treatments available for canker sores?
Recent research has shown that light-emitting devices like The Luminance RED can be effective in stopping pain and reducing healing time. The technology is still very new but we expect to see a lot more of it in the near future.
Q: Does stress cause canker sores?
Many people report getting canker sores during times of higher stress, so it seems likely there’s a link, though we don’t fully understand it.
Q: Does COVID-19 cause canker sores?
Canker sores have not been considered a core symptom of COVID-19 to date. Some coronavirus patients have experienced mouth rashes unrelated to canker sores. There have been anecdotal reports of canker sores during COVID-19, but this may be due to stress or other reasons.
Q: Does HIV/AIDS cause canker sores?
No. Canker sores are not a symptom of HIV. However, if a person gets canker sores and has HIV, they may struggle to heal and have more severe symptoms.
Q: Why do kids get canker sores? How do I treat my child’s canker sores?
Canker sores are most common in children and adolescents, so don’t be alarmed if your child gets them from time to time. The precise cause is unknown, but most kids experience light to moderate symptoms and sores heal after about a week. Treatment options for a child’s canker sores are the same as what an adult would use: gels, mouthwashes, antibiotics, home remedies, light therapy, or occasionally antibiotics in severe cases.
Q: Does pregnancy cause canker sores? Why do you get canker sores when you’re pregnant?
Some women experience canker sores with more frequency during their first trimester, when hormone levels are surging. Anecdotally, people report getting canker sores when they’re under higher stress and pressure, which can describe many expectant parents.
Q: Can you get canker sores from braces? Why do braces cause canker sores?
Many people report canker sores when they get braces or experience irritation from braces. The braces can rub up against the lining of the mouth and cause acute irritation.
Q: What are the types of canker sores?
Canker sores are classified as minor (small, heal within a week), major (larger, longer than a week to heal), or herpetiform (clusters of very small sores). Minor canker sores are the most common, at about 80% of all cases.
Q: What are herpetiform canker sores?
Fewer than 5% of people experience herpetiform canker sores, which form as clusters of very small ulcers that can merge together into larger sores. Herpetiform canker sores usually heal in about a week like minor canker sores, but may be more painful before they heal. 
Q: Are there OTC over the counter treatments for canker sores?
Common over-the-counter canker sore products like Kank-A®, Zilactin® and Orajel® are used to lessen pain.
Q: What are natural home remedies for canker sores?
People have reported anecdotal relief with hundreds of natural, at-home methods over the years. Gargling salt water for canker sores is an old standard. Other remedies people use include mouthwash, baking soda, hydrogen peroxide, lysine, clove oil, essential oils, honey, vitamin C, vitamin b12, coconut oil, and silver nitrate. None of these methods have been widely tested in clinical trials.
Q: Who gets canker sores?
The precise cause of canker sores is unknown, but roughly 50% of the population may get them at some point. Canker sores are more common in kids and teens, women, and people whose parents get canker sores.
Q: Are canker sores related to immune or autoimmune diseases like lupus, celias, and Crohn’s?
Maybe. The link between immune disorders and canker sores is not fully understood, but people who experience canker sores commonly do have an immune disorder like IBS, lupus, celiac disease, ulcerative colitis, Crohn’s disease, AIDS, or Behcet’s disease. 
Q: Do spicy and acidic foods cause canker sores?
Some people get canker sores by eating acidic foods like citrus fruits or tomatoes. What is more clear is that when you have canker sores, eating spicy and acidic foods can make them worse, and very painful.
Q: Do anti-inflammatory drugs like aspirin and ibuprofen cause canker sores?
Possibly. Canker sores have been a reported side effect of using nonsteroidal anti-inflammatory drugs like aspirin and ibuprofen, though the exact link is not known.
Q: Can toothpaste or brushing cause canker sores?
Some toothpaste ingredients may cause canker sores in certain people. Brushing injuries and other oral traumas may cause ulcers that look similar to canker sores.
Q: Canker sore or oral mucositis?
Oral mucositis or “OM” is a side effect of cancer treatments that causes painful mouth ulcers. Canker sores are not a symptom of chemotherapy or radiation treatments like OM, and canker sores are typically less painful.
Learn more about canker sores, canker sore treatments, canker sore identification, and how light therapy is used to treat canker sores.