Most canker sores heal on their own in one to two weeks, but several treatments can cut the pain within hours and speed closure by days. The fastest relief tends to come from topical numbing agents or chemical cauterization, while corticosteroid pastes and barrier gels work to shorten overall healing time. Which approach makes sense depends on how painful the sore is, how often you get them, and whether you can get to a dentist or need something from the drugstore shelf right now.
Numbing the Pain Immediately
When a canker sore is throbbing and you need to eat, talk, or just get through the day, over-the-counter numbing products are the quickest fix. Gels and liquids containing benzocaine or lidocaine block nerve signals at the sore’s surface, dulling pain within minutes of application.1PubMed Central. An overview of local anesthetics in over-the-counter products These are available in several forms: gels you dab directly on the sore, liquids you swab with a cotton tip, and even small adhesive patches.
The relief is real but temporary, usually lasting 20 to 40 minutes before the numbness wears off. You can reapply multiple times a day following the product’s directions. These products do not speed healing; they just make the sore tolerable while your body does the repair work. Think of them as a bridge, something to pair with a treatment that actually shortens healing time.
Silver Nitrate Cauterization
If you want dramatic pain reduction from a single treatment, silver nitrate cauterization is one of the most studied options. A small applicator stick coated in silver nitrate is touched to the ulcer for a few seconds, chemically sealing the exposed nerve endings. In a randomized controlled trial, about 70% of patients treated with silver nitrate had a meaningful drop in pain the very next day, compared with roughly 11% in the placebo group.2British Journal of Dermatology. Silver nitrate cautery in aphthous stomatitis: A randomized controlled trial The application itself stings for a few seconds, and the sore may turn white or gray temporarily.
One important detail: silver nitrate relieved pain but did not make the ulcer close any faster. By day seven, healing rates were nearly identical between treated and untreated groups.2British Journal of Dermatology. Silver nitrate cautery in aphthous stomatitis: A randomized controlled trial So cauterization is best understood as a pain intervention, not a healing accelerator. Silver nitrate sticks are sometimes available at pharmacies, but many people have this done in a dentist’s or doctor’s office for precision and safety.
Topical Corticosteroid Pastes
For actually shrinking the ulcer and speeding up tissue repair, topical corticosteroids are the most commonly recommended prescription-strength option. Triamcinolone acetonide paste, often sold as Kenalog in Orabase, is applied directly over the sore a few times a day. The steroid tamps down the local immune overreaction that keeps the sore inflamed and painful. Other options include fluocinonide gel and clobetasol, with potency increasing as the sore’s severity warrants it.
Corticosteroid pastes work best when you catch the sore early, ideally during the tingling or redness stage before the ulcer fully opens. Once the crater has formed, they still help but less dramatically. A common mistake is applying the paste and then immediately eating or drinking, which washes it away. Dab the paste on after meals and before bed, and try not to disturb it with your tongue for at least 20 to 30 minutes. Some formulations combine the steroid with an adhesive base that sticks to the moist tissue, and these tend to stay put longer.
Barrier Films and Hyaluronic Acid
A newer category of treatment works by physically shielding the sore from saliva, food, and friction. Products containing hyaluronic acid, available as gels or rinses, form a protective film over the ulcer while also promoting tissue hydration and repair. In a retrospective study of patients using hyaluronic acid products, the gel formulation showed a noticeable edge in early improvement: about 72% of sores treated with the gel had measurable size reduction within three days, compared with 40% in the rinse group.3BMC Oral Health. Treatment of recurrent aphthous stomatitis (RAS; aphthae; canker sores) with a barrier forming mouth rinse or topical gel formulation containing hyaluronic acid: a retrospective clinical study By one week, both forms achieved roughly 80% lesion reduction, with complete closure in over half the cases.3BMC Oral Health. Treatment of recurrent aphthous stomatitis (RAS; aphthae; canker sores) with a barrier forming mouth rinse or topical gel formulation containing hyaluronic acid: a retrospective clinical study
The advantage of barrier products is that they are generally well tolerated, do not require a prescription, and can be layered with other treatments. You might use a numbing gel for immediate pain relief and then apply a hyaluronic acid gel 15 minutes later as a protective coating. The gel format seems to outperform the rinse for speed, probably because it physically stays on the sore longer.
Salt Water, Baking Soda, and Other Rinses You Already Have
Dissolving half a teaspoon of salt or baking soda in a glass of warm water and swishing it around the sore for 30 to 60 seconds is one of the oldest and cheapest interventions. The osmotic effect of salt draws fluid out of swollen tissue, temporarily reducing inflammation. Baking soda neutralizes acids in the mouth that can irritate the open sore. Neither ingredient is going to close the ulcer overnight, but regular rinsing, three or four times a day, keeps the area cleaner and can make the sore less painful between meals.
Research on saline and baking soda rinses for oral mucosal lesions, though largely conducted in patients with chemotherapy-related mucositis rather than ordinary canker sores, has shown meaningful pain reduction after several days of consistent use.4Academia.edu. Effectiveness of Oral Care Using Normal Saline and Baking Soda Towards Pain and Comfort in Mucositis Patients Undergoing Chemotherapy That population’s mouth sores are more severe than a typical canker sore, so the benefits in milder cases likely hold up. Just avoid making the solution too concentrated; a strongly salty rinse on an open ulcer will sting and can irritate surrounding tissue.
Honey as a Topical Treatment
Dabbing a small amount of honey directly on a canker sore sounds like folk medicine, but there is a reasonable evidence base behind it. Honey has natural antibacterial properties and creates a moist, slightly acidic environment that supports tissue repair. A systematic review of honey for oral ulcerative lesions found it relieved symptoms earlier than untreated controls, with reduced pain and no adverse effects.5Exploratory Research and Hypothesis in Medicine. The Effect of Honey as a Treatment for Oral Ulcerative Lesions: A Systematic Review
The practical trick is keeping honey on the sore long enough for it to work. Apply a thick dab after meals and before bed, and resist the urge to swallow immediately. Medical-grade honey products, including manuka honey formulations marketed specifically for oral wounds, may offer more consistent potency than the jar in your pantry, though ordinary honey is not worthless. This is a reasonable option when you do not have access to a pharmacy or prefer something more natural, but it works best as a complement to other treatments rather than a standalone strategy for getting rid of a sore fast.
Low-Level Laser Therapy at the Dentist
If you get canker sores frequently and want an in-office option that works quickly, low-level laser therapy is worth knowing about. A dentist applies a low-power laser directly to the ulcer for one to two minutes, and the effect on pain can be almost immediate. In one controlled trial, 28 out of 30 patients had complete pain relief right after a single laser session. Even more striking, ulcers in the treated group resolved in about three days on average, compared with nearly nine days in the sham-treated group.6PubMed Central. Efficacy of Low-Level Laser Therapy in Treatment of Recurrent Aphthous Ulcers – A Sham Controlled, Split Mouth Follow Up Study
A systematic review and meta-analysis confirmed the general pattern: low-level laser therapy is associated with both immediate pain relief and faster healing.7PubMed Central. Effectiveness of low-level laser therapy in reducing pain score and healing time of recurrent aphthous stomatitis: a systematic review and meta-analysis The treatment is painless, has no known side effects at these energy levels, and takes only a few minutes. The catch is access and cost: not every dental office has the equipment, and insurance does not always cover it. For people who deal with recurrent canker sores multiple times a year, though, the combination of instant pain relief and roughly halved healing time makes it one of the more impressive options available.
Triggers Worth Removing
Getting rid of the sore you have right now is only half the picture if you keep getting new ones. Several modifiable triggers are well supported by evidence, and removing them can reduce the frequency and severity of future outbreaks.
Your toothpaste might be part of the problem. Sodium lauryl sulfate, a foaming agent in most mainstream toothpastes, irritates the oral mucosa and is linked to more frequent canker sores. A systematic review found that switching to an SLS-free toothpaste reduced the number of ulcers, their duration, the number of episodes, and pain across all eligible trials.8PubMed Central. Effect of sodium lauryl sulfate on recurrent aphthous stomatitis: A systematic review SLS-free options are widely available, and this single swap may be the easiest preventive measure you can take.
Nutritional gaps also play a role. People with recurrent canker sores tend to have lower dietary intake of vitamin B12 and folate compared with the general population. One study found that canker sore sufferers consumed about 7% less of the recommended daily B12 and roughly 20% less folate than matched controls.9Journal of Oral Pathology & Medicine. Reduced dietary intake of vitamin B12 and folate in patients with recurrent aphthous stomatitis Iron deficiency has also been implicated. If you get canker sores regularly, it is worth asking your doctor to check these levels. Correcting a deficiency will not heal the sore you have today, but it can reduce how often new ones appear.
Stress and emotional state are another well-documented trigger. Research has found that people with recurrent canker sores report higher levels of stress, anger, and anxiety than controls, and that the relationship between stress and outbreaks appears to be mediated by a person’s baseline level of anger and anxiety.10Europe PMC. Recurrent aphthous stomatitis: stress, trait anger and anxiety of patients This does not mean you can think your way out of canker sores, but it does help explain why outbreaks cluster around exams, deadlines, and life upheavals. Managing stress through whatever works for you, whether that is exercise, sleep hygiene, or professional support, is a legitimate prevention strategy.
Mechanical trauma is another common culprit that deserves mention. Biting your cheek, a sharp edge on a tooth or braces bracket, or vigorous brushing with a hard-bristled toothbrush can all trigger a sore in a susceptible person. Switching to a soft-bristled brush and getting sharp dental edges smoothed down removes an ongoing source of irritation.
Why Canker Sores Happen in the First Place
Understanding the underlying mechanism helps explain why treatments work the way they do. The current scientific view is that canker sores result from a misdirected local immune response. A minor trigger, be it a bite, a food irritant, or stress, sets off an excessive accumulation of certain immune cells in the oral lining, which then damage the tissue and create the open ulcer.11PubMed Central. Genome wide analysis for mouth ulcers identifies associations at immune regulatory loci This is why corticosteroids, which suppress that immune flare, are effective at shortening healing. It is also why people with autoimmune conditions or genetic predispositions tend to get canker sores more often and more severely.
The mouth’s microbial community also plays a supporting role. Disruption of the normal oral microbiome can weaken the mucosal barrier and make the tissue more vulnerable to ulceration.12Europe PMC. Oral microbiota dysbiosis accelerates the development and onset of mucositis and oral ulcers Harsh mouthwashes, antibiotics, and poor oral hygiene can all shift the microbial balance. Gentle oral care, an alcohol-free mouthwash, regular brushing without overdoing it, tends to keep the bacterial ecosystem more stable.
When You Should See a Doctor
Most canker sores are annoying but harmless, and a combination of the strategies above will get you through them. But some patterns warrant professional evaluation. If your sores are unusually large (bigger than a centimeter), last longer than three weeks, come in clusters, or recur so frequently that you are rarely without one, you may need prescription-strength treatment or testing for an underlying condition.
Several systemic diseases can cause mouth ulcers that look just like canker sores but are not. These include celiac disease, inflammatory bowel disease, and Behçet disease, among others.13JADA / Elsevier. Recurrent aphthous ulcers: a review of diagnosis and treatment Your doctor or dentist can help distinguish ordinary canker sores from something that needs a different workup. It is also easy to confuse canker sores with oral herpes simplex lesions, which look similar but have a viral cause and respond to antiviral treatment instead.13JADA / Elsevier. Recurrent aphthous ulcers: a review of diagnosis and treatment
For truly refractory cases, where sores keep coming back despite all local measures, systemic medications enter the picture. Colchicine is often considered the first-line systemic option for severe or complex recurrent canker sores, with evidence showing it can reduce pain, decrease the number of lesions, and lengthen the gap between outbreaks.14PubMed Central. Colchicine in the treatment of refractory aphthous ulcerations: Review of the literature and two case reports Other systemic options include pentoxifylline and short courses of oral prednisolone, though the evidence for these is more debated.15PubMed Central. The treatment of chronic recurrent oral aphthous ulcers Stronger immunosuppressive drugs are generally reserved for ulcers linked to Behçet disease or similarly serious conditions.
Putting Together a Practical Plan
If you have a canker sore right now and want it gone as fast as possible, here is how the treatments layer together in practice:
- For immediate pain: Apply an over-the-counter benzocaine or lidocaine gel directly to the sore. Reapply as needed before meals and whenever the pain spikes.
- For faster healing: Use a topical corticosteroid paste or a hyaluronic acid gel, ideally starting as soon as you notice the sore forming. Apply after meals and at bedtime.
- For a clean environment: Rinse with warm salt water or a baking soda solution several times a day, especially after eating. Avoid alcohol-based mouthwashes, which can sting and slow recovery.
- For prevention going forward: Switch to an SLS-free toothpaste, check your B12 and folate intake, and address any obvious mechanical irritants in your mouth.
If you can get to a dentist and they have a low-level laser, a single session can provide near-instant pain relief and substantially shorten healing. If you cannot get to a dentist and want a one-shot pain fix, asking your doctor about silver nitrate cauterization is a reasonable alternative, though it will not speed the healing timeline. For people who get canker sores repeatedly, the trigger-removal measures, especially ditching SLS toothpaste and correcting nutrient deficiencies, tend to pay off more over time than any single treatment applied to each individual sore.