Most canker sores heal on their own within one to two weeks, but a handful of home strategies can cut that timeline shorter and make the interim less miserable. No single remedy works overnight, so the most effective approach combines something to numb the pain, something to protect the ulcer from further irritation, and a few habit changes that keep new sores from forming. The good news is that the remedies with the best evidence behind them are cheap, widely available, and easy to use.
Saltwater and Baking Soda Rinses
The simplest home treatment is a warm saltwater rinse: roughly half a teaspoon of table salt dissolved in a cup of warm water, swished around the mouth for 30 seconds a few times a day. Salt draws fluid out of inflamed tissue through osmosis, which temporarily reduces swelling and can ease the sting. A baking soda rinse (same ratio) works on a slightly different principle, neutralizing acids in the mouth that irritate exposed tissue. Both are safe for most people, though concentrated salt solutions can irritate gums, and one study found that a nearly saturated sodium chloride mouthwash combined with a baking soda–hydrogen peroxide paste caused gum tissue peeling in all treated subjects.1PubMed Central. Local and systemic effects of orally applied sodium salts The practical lesson: keep concentrations mild. You want a gently salty solution, not brine.
Honey Applied Directly to the Sore
Honey has a long folk-medicine reputation for wound healing, and research supports it for oral ulcers specifically. In an animal study comparing two forms of honey application, a honey gel significantly outperformed a control group in healing oral ulcers by days three and seven, and the gel form worked better than a mucoadhesive honey preparation.2PubMed Central. Effect of two different delivery systems of honey on the healing of oral ulcer in an animal model The mechanism likely involves honey’s natural antibacterial compounds and its ability to form a protective coating over the wound. You can dab a small amount of raw honey directly onto the sore a few times a day, ideally after meals and before bed. It will sting briefly, then the coating tends to soothe. Manuka honey is frequently recommended because of its higher antibacterial activity, though any raw, unprocessed honey should offer some benefit.
Alum Powder
Alum, the astringent crystal sold in the spice aisle for pickling, is one of the more underrated home remedies. It works by drawing moisture from the ulcer and tightening the surrounding tissue, which creates a kind of chemical cauterization without actual heat. In a clinical trial, patients who applied alum to their canker sores recovered in an average of about seven and a half days, compared to roughly twelve days for a control group. Pain and ulcer size were also significantly reduced at one, three, and five days after treatment.3PubMed Central. Efficacy of alum for treatment of recurrent aphthous stomatitis To use it, wet your finger, dip it into alum powder, and press it against the sore for about a minute. Rinse your mouth afterward. It tastes bitter and the initial contact stings, but the area usually feels better within a few hours. You can repeat this once a day until the sore shrinks.
Dilute Hydrogen Peroxide
A rinse made from equal parts 3% hydrogen peroxide and water is another common home approach. Hydrogen peroxide is an antiseptic, and its fizzing action physically clears debris from the wound surface. A review of dental uses found that daily use of 3% hydrogen peroxide or lower concentrations showed only occasional, temporary irritation, and that topically applied hydrogen peroxide actually enhanced wound healing after oral surgery because of its antimicrobial effects.4PubMed. Hydrogen peroxide: a review of its use in dentistry The key is dilution. Swishing full-strength peroxide or using higher-concentration products can damage tissue, especially with repeated exposure. Stick to the drugstore 3% bottle, mix it with water, swish for about 30 seconds, and spit. Two to three times a day is enough.
Over-the-Counter Pain Relief and Protective Gels
When you need fast pain relief, the most accessible option is a benzocaine gel (sold under brand names like Orajel and Anbesol). Benzocaine numbs the nerve endings at the ulcer surface and provides near-immediate, if short-lived, relief. In a clinical trial comparing several topical agents, 20% benzocaine gel provided significant pain relief, though it was less effective at reducing the overall size and duration of ulcers compared to prescription options like triamcinolone acetonide and amlexanox.5PubMed Central. A Randomized, Double-Blind, Placebo-Controlled Trial on Clinical Efficacy of Topical Agents in Reducing Pain and Frequency of Recurrent Aphthous Ulcers A separate comparative study similarly found that benzocaine demonstrated efficient numbing but slower overall recovery.6Journal of Neonatal Surgery. Investigating the Therapeutic Impact of Choline Salicylate Gel, Benzocaine, Lidocaine, Amlexanox, and Povidone-Iodine in the Treatment of Mouth Ulcers: A Comparative Study of Five Different Therapeutic Agents
In other words, benzocaine is great for getting through a painful meal or a workday, but it is not doing much to speed actual healing. For that, you want a product that also forms a physical barrier over the ulcer. Mucoadhesive patches and films that stick to the sore and shield it from friction and saliva are increasingly available over the counter.7PubMed Central. Evolution of Drug Delivery Systems for Recurrent Aphthous Stomatitis Some combine a numbing agent with the barrier material, which gives you both pain relief and protection in one step. If your pharmacist carries canker sore patches, they are worth trying, especially for sores on the inner lip or cheek where they get constantly bumped by teeth.
Switch to an SLS-Free Toothpaste
This is one of the easiest changes you can make and one of the most overlooked. Sodium lauryl sulfate (SLS) is the foaming agent in most mainstream toothpastes. It is also a detergent that strips the protective mucus layer off your mouth’s lining. A systematic review of clinical trials found that switching to an SLS-free toothpaste significantly reduced the number of canker sores, the duration of each episode, and the pain associated with them.8PubMed. Effect of sodium lauryl sulfate on recurrent aphthous stomatitis: A systematic review A separate trial confirmed that an SLS-free formulation caused significantly fewer and less severe oral lesions compared to a standard SLS toothpaste within just 30 minutes of use.9PubMed. A randomised clinical study comparing the effect of Steareth 30 and SLS containing toothpastes on oral epithelial integrity (desquamation) And another study found that SLS-free toothpaste decreased ulcer count and soreness regardless of the patient’s sex.10Kufa Journal for Nursing Sciences. The Role of Sodium Lauryl Sulfate as a Causative Agent of Recurrent Aphthous Ulceration
If you get canker sores more than a few times a year, this is the single most impactful prevention measure supported by research. Check the ingredients list on your tube. If you see sodium lauryl sulfate, switch. Brands that omit SLS are easy to find online or at most pharmacies. Your toothpaste will foam less, which feels odd for a few days, but you adjust quickly.
Nutritional Gaps That Feed the Cycle
Recurrent canker sores are sometimes a signal that your body is missing specific nutrients. Research has found that people who get frequent canker sores consume lower levels of vitamin B12 and folate than the general population, and that they are more likely to have lower blood levels of both.11PubMed Central. Reduced dietary intake of vitamin B12 and folate in patients with recurrent aphthous stomatitis Iron deficiency is another well-documented connection: one study found that about two-thirds of canker sore patients had decreased ferritin (the body’s iron storage marker).12PubMed Central. Significance of ferritin in recurrent oral ulceration The proposed explanation is that low iron impairs the body’s ability to maintain healthy oral lining tissue and mount a proper immune response.13Atlantis Press. The Relationship between Recurrent Aphthous Stomatitis and Iron Deficiency Anemia
None of this means you should start megadosing supplements the moment a canker sore appears. A single sore after biting your cheek is not a nutrient deficiency. But if you get sores four, five, or more times a year with no obvious trigger, it is worth asking your doctor to check your iron, B12, and folate levels. Correcting a genuine deficiency can dramatically reduce how often sores come back. Good dietary sources of B12 include meat, fish, eggs, and fortified cereals. Folate is abundant in leafy greens, legumes, and citrus. Iron comes from red meat, lentils, and spinach, though plant-based iron absorbs better when eaten with vitamin C.
Stress, Sleep, and Other Triggers Worth Managing
If you notice canker sores showing up during exam weeks, work deadlines, or rough patches in your personal life, that pattern is real. A survey of over a thousand dental students found that about a third reported a history of recurrent canker sores, and among those, more than a quarter identified a direct connection between stress and their outbreaks.14PubMed Central. Recurrent Oral Ulcers and Its Association With Stress Among Dental Students in the Northeast Indian Population Stress hormones influence immune function and inflammation, both of which affect how the oral lining repairs itself. You cannot eliminate stress, but you can note the pattern and preemptively use protective strategies (an SLS-free toothpaste, a saltwater rinse before bed) during high-stress periods.
Sleep matters too. An animal study found that sleep deprivation worsened existing oral ulcers and delayed their healing, alongside increases in inflammatory markers and stress hormones.15PubMed Central. Sleep deprivation worsened oral ulcers and delayed healing process in an experimental rat model While animal studies do not translate directly to humans, the link between poor sleep and impaired wound healing is well established in human research across many wound types. When you are dealing with an active canker sore, getting enough rest is not just general wellness advice; it directly supports the healing process.
Mechanical trauma is another consistent trigger. Canker sores tend to appear at sites where tissue has been physically damaged: the spot where a sharp chip scratched the inside of your cheek, the area a new retainer rubs, or the lip you accidentally bit.16Medical Hypotheses. Aphthous stomatitis (canker sores): A consequence of high oral submucosal viscosity If you have dental hardware, a rough filling, or a habit of chewing the inside of your cheek, fixing those sources of repeated trauma may do more long-term good than any topical remedy.
Chamomile and Other Herbal Options
Chamomile tea bags pressed against a canker sore are a popular home remedy, and there is some science behind the idea. Chamomile contains anti-inflammatory compounds, and researchers have developed chamomile extract pastilles specifically designed for oral ulcer treatment, formulated for controlled release and better palatability than raw chamomile.17Acta Biochimica Iranica. Development and Optimization of Chamomile Extract Pastilles for Potential Oral Ulcer Treatment Those specialized pastilles are not yet widely available commercially, but you can approximate the idea at home by brewing a chamomile tea bag, letting it cool, and pressing it against the sore for a few minutes. The warm compress itself increases blood flow to the area, and the chamomile provides mild anti-inflammatory and antiseptic effects. It will not resolve a sore on its own, but it is a gentle add-on that is unlikely to cause any harm.
When Home Remedies Are Not Enough
Most canker sores are minor and respond well to the approaches described above. But there are situations where you should see a dentist or doctor rather than continuing to self-treat:
- Sores lasting more than three weeks: a typical canker sore heals within 10 to 14 days. Anything persisting well beyond that timeline warrants professional evaluation.
- Unusually large ulcers: major canker sores (larger than a centimeter across) heal slowly and can scar. They sometimes benefit from prescription-strength topical steroids.
- Frequent recurrence: if you are never fully free of ulcers or get new crops every few weeks, your doctor should investigate underlying causes.
- Systemic symptoms: fever, fatigue, weight loss, or persistent diarrhea alongside mouth ulcers can point to conditions like celiac disease, Crohn’s disease, or other autoimmune disorders. Canker-sore-like ulceration has been reported in up to about a quarter of Crohn’s disease patients.18PubMed Central. Oral manifestations of gastrointestinal disorders
Prescription options include topical corticosteroid pastes (like triamcinolone acetonide), which a clinical trial found significantly more effective than over-the-counter options at reducing ulcer size, pain, and redness.5PubMed Central. A Randomized, Double-Blind, Placebo-Controlled Trial on Clinical Efficacy of Topical Agents in Reducing Pain and Frequency of Recurrent Aphthous Ulcers For severe cases, doctors may prescribe systemic medications. These are not home remedies, but knowing they exist is useful if your home efforts consistently fall short.
Low-Level Laser Therapy
This one straddles the line between professional treatment and future home remedy. Low-level laser therapy (LLLT) uses a small diode laser applied directly to the ulcer for a few minutes. In a controlled clinical trial, canker sores treated with the active laser healed in an average of about three days, compared to roughly nine days in the sham-laser group. Nearly all patients experienced complete pain relief immediately after treatment.19PubMed Central. Efficacy of Low-Level Laser Therapy in Treatment of Recurrent Aphthous Ulcers – A Sham Controlled, Split Mouth Follow Up Study Case reports have also documented successful and rapid healing of oral ulcers with diode laser treatment.20PubMed Central. Low laser therapy as an effective treatment of recurrent aphtous ulcers: a clinical case reporting two locations
Right now, LLLT is primarily available at dental offices. But consumer-grade red-light and near-infrared devices are increasingly marketed for at-home use, and some dentists are beginning to recommend them to patients with frequent recurrences. The devices are not cheap, and evidence specific to the consumer versions is limited. If you suffer from frequent, debilitating canker sores and have tried everything else, ask your dentist whether in-office laser treatment is available and whether a home device might be appropriate for you.
Putting Together a Practical Routine
When a canker sore first appears, you do not need to pick just one remedy. A reasonable approach for the first few days looks something like this: rinse with warm saltwater or diluted hydrogen peroxide after meals. Apply a dab of honey or alum powder directly to the sore once or twice a day. Use a benzocaine gel or adhesive patch before meals or whenever pain is interfering with your day. Avoid crunchy, acidic, and spicy foods that scrape or irritate the wound. Brush gently with an SLS-free toothpaste.
For prevention, the evidence points to three big-picture interventions: switching permanently to SLS-free toothpaste, addressing any nutritional deficiencies through diet or supplementation (after testing, not guessing), and reducing sources of chronic oral trauma like sharp dental edges or habitual cheek-biting. Managing stress and prioritizing sleep will not single-handedly prevent canker sores, but they reduce the frequency in people whose outbreaks are clearly stress-linked. None of these strategies are dramatic on their own. Together, they tend to make recurrences noticeably less frequent and less severe when they do happen.