Topical corticosteroid gels and pastes are the fastest evidence-backed way to shrink a canker sore and relieve its pain, often cutting healing time by several days compared to doing nothing. But the landscape of treatments runs from prescription options all the way down to drugstore gels and kitchen-shelf remedies, and not all of them perform equally. How quickly you act matters too: most treatments work best when applied at the first sign of tingling or soreness, before the ulcer fully forms.
Topical Corticosteroids Are the First-Line Treatment
If you want a canker sore gone as fast as possible, a topical corticosteroid is the go-to option backed by the most clinical evidence. These come in gels, pastes, and rinses, with common options including triamcinolone acetonide paste, fluocinonide gel, and dexamethasone rinse. A systematic review of trials found that, on average, ulcers healed faster and with less pain when treated with topical corticosteroids compared to placebo.1Acta Otorrinolaringologica (English Edition). Topical Corticosteroids in Recurrent Aphthous Stomatitis. Systematic Review The key is to start applying as early as you can. Dabbing the paste directly onto the sore two to four times a day, especially after meals and before bed, gives the medication the most contact time with the ulcer.
You can get milder formulations over the counter in some countries, while stronger ones require a prescription. Your dentist or doctor can help decide which strength makes sense based on how frequently you get canker sores and how large they tend to be. For people who get sores in hard-to-reach spots, a dexamethasone mouth rinse can coat the area without requiring precise application.
Amlexanox Paste
Amlexanox 5% paste is a prescription topical treatment that works differently from corticosteroids. Rather than suppressing inflammation broadly, it targets specific inflammatory and allergic pathways. Across multiple large trials, applying the paste four times daily significantly sped up complete healing and pain resolution. Patients using it had more fully healed ulcers by day three compared to those using nothing, and by day four compared to those using an inactive paste. Pain relief showed up even earlier, with significantly more patients reporting complete pain resolution by day two versus no treatment and by day three versus placebo.2PubMed. Amlexanox for the treatment of recurrent aphthous ulcers
Amlexanox was marketed in the United States as Aphthasol but has been discontinued in some markets, so availability varies by region. Where it is available, it remains a solid choice for people who want an alternative to steroids or who get canker sores frequently enough that repeated corticosteroid use becomes a concern.
Barrier Gels and Hyaluronic Acid Products
Over-the-counter barrier-forming products take a different approach: rather than fighting inflammation directly, they coat the ulcer surface to protect it from food, saliva, and further irritation. Many of these contain hyaluronic acid, which helps retain moisture and supports tissue repair. In a retrospective study comparing a hyaluronic acid mouth rinse and a hyaluronic acid gel, both groups saw significant pain reduction and lesion shrinkage. After seven days, roughly 60% of rinse users and 56% of gel users had complete closure. The gel group had an edge early on, with about 72% showing improvement in lesion size within three days versus 40% for the rinse.3PubMed Central. 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
Brands like Orajel, Kank-A, and various hyaluronic acid gels are widely available at pharmacies. Benzocaine-containing products numb the pain on contact, which is useful for eating and drinking, though they do not speed actual healing. If your main complaint is pain rather than duration, a numbing gel can make a canker sore livable within seconds, even if the ulcer itself takes its normal course underneath.
Low-Level Laser Therapy
If you have access to a dentist who offers it, low-level laser therapy is one of the more dramatic options. A sham-controlled trial found that ulcers treated with an active laser healed in about three days on average, compared to roughly nine days in the sham group. Even more striking, 28 out of 30 patients in the laser group experienced complete pain relief immediately after a single application.4PubMed Central. Efficacy of Low-Level Laser Therapy in Treatment of Recurrent Aphthous Ulcers – A Sham Controlled, Split Mouth Follow Up Study A 2024 meta-analysis pooling results across multiple studies confirmed that laser treatment consistently reduced both pain scores and healing time.5PubMed 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 catch is practical. Laser treatment requires a visit to a dental or medical office equipped with the right device, and the treatment may not be covered by insurance. It also does not help with prevention. But for someone dealing with a painful canker sore right now, especially a large one, a single laser session can essentially cut the misery short.
Honey and Other Home Remedies
Honey has genuine anti-inflammatory and wound-healing properties, and animal research has shown it can speed the healing of oral ulcers. In a study on rats with experimentally induced mouth ulcers, honey gel produced significantly better healing at three and seven days compared to no treatment.6PubMed Central. Effect of two different delivery systems of honey on the healing of oral ulcer in an animal model The limitation is that this was an animal study, and well-controlled human trials specifically on honey for canker sores are sparse. Still, honey is safe to apply topically to a canker sore, and many people find it soothing. Raw or medical-grade honey dabbed on the sore a few times daily is a reasonable low-risk option if you don’t have access to a pharmacy.
Saltwater rinses are probably the most common home remedy, and they make physiological sense: a mild saline solution can help draw fluid from inflamed tissue and create an environment less friendly to bacteria. There is limited controlled trial data specifically testing saltwater against placebo for canker sores, but the practice is widely recommended by dentists and carries essentially no risk. A half teaspoon of salt in a cup of warm water, swished gently for 30 seconds, is the standard approach.
Baking soda rinses, on the other hand, deserve more skepticism than they usually get. A systematic review looking at sodium bicarbonate for oral mucosal lesions found no evidence supporting its use for treatment or prevention, and noted that the sudden pH increase it causes could actually be counterproductive and delay proper treatment.7BMC Oral Health. Prevention and the treatment of oral mucositis: the efficacy of sodium bicarbonate vs other agents: a systematic review That review focused on oral mucositis rather than canker sores specifically, but the takeaway is that baking soda is not the harmless cure-all that home remedy lists make it out to be.
Why You Keep Getting Canker Sores
Understanding what triggers canker sores is the other half of getting rid of them, because the fastest way to deal with one is to stop the next one from forming. The underlying cause remains officially unclear, but the condition is considered multifactorial, involving genetic predisposition, immune system disturbances, and a range of environmental triggers.8PubMed Central. Management of oral aphthous ulcer: A review
Stress is one of the best-documented triggers. A study tracking patients over time found that experiencing a stressful life event nearly tripled the odds of a canker sore episode. Mental stressors had a bigger impact than physical ones, increasing the odds roughly threefold compared to about a 44% increase for physical stressors.9PubMed Central. Effect of stressful life events on the onset and duration of recurrent aphthous stomatitis Interestingly, stress was linked to whether a canker sore appeared at all but not to how long it lasted once it showed up. Separate research found that people with recurrent canker sores reported higher levels of anger and anxiety than controls, and that these emotional states amplified the effect of stress.10PubMed. Recurrent aphthous stomatitis: stress, trait anger and anxiety of patients
Nutritional deficiencies also play a role. People with recurrent canker sores tend to consume less vitamin B12 and folate than the general population.11PubMed Central. Reduced dietary intake of vitamin B12 and folate in patients with recurrent aphthous stomatitis A trial of B12 supplementation found that about 96% of participants who took cyanocobalamin (a form of B12) saw a decrease in ulcer frequency, and this held true even in patients whose B12 blood levels were already in the normal range.12PubMed. Cyanocobalamin may be beneficial in the treatment of recurrent aphthous ulcers even when vitamin B12 levels are normal That is a somewhat surprising finding and suggests that higher B12 levels may offer mucosal protection beyond what is needed to avoid outright deficiency. Iron and folate are also commonly mentioned as factors, particularly in combination with B12.
The Celiac Connection
Recurrent canker sores are one of the most common oral signs of celiac disease, and this connection is underappreciated. A systematic review spanning over 1,300 celiac patients found that about 34% had recurrent canker sores, compared to roughly 13% of healthy controls.13MDPI (Journal of Clinical Medicine). Beyond the Gut: A Systematic Review of Oral Manifestations in Celiac Disease If you get frequent canker sores and also experience digestive symptoms like bloating, diarrhea, or unexplained weight loss, it may be worth asking your doctor about celiac testing. In some celiac patients, adopting a strict gluten-free diet reduces or eliminates the ulcers entirely, which makes sense given that the underlying intestinal inflammation impairs nutrient absorption and triggers the kind of immune dysregulation that drives canker sore formation.
Other gastrointestinal conditions such as Crohn’s disease and ulcerative colitis are also associated with recurrent mouth ulcers.14Springer Link. Etiopathogenesis of recurrent aphthous stomatitis and the role of immunologic aspects: literature review The common thread appears to be immune-mediated inflammation that affects mucosal surfaces throughout the body, not just the gut.
Switching Your Toothpaste
One of the simplest prevention strategies is also one of the least well-known: switching to a toothpaste that does not contain sodium lauryl sulfate (SLS). SLS is the foaming agent in most commercial toothpastes, and it can irritate the oral mucosa. A systematic review of trials comparing SLS-free and SLS-containing toothpastes found that the SLS-free versions significantly reduced the number of ulcers, the duration of each ulcer, the number of episodes, and the level of pain.15PubMed. Effect of sodium lauryl sulfate on recurrent aphthous stomatitis: A systematic review That is a consistent effect across all four measures, which is fairly convincing.
SLS-free toothpastes are not hard to find. Brands like Sensodyne, Biotene, and several others market SLS-free formulations, and they clean teeth just as effectively. If you get canker sores even a few times a year, this is one of the first things worth trying. It costs nothing extra and the potential downside is zero.
Hormonal Triggers and the Menstrual Cycle
Many women report that canker sores appear in a predictable pattern tied to their menstrual cycle, often flaring just before menstruation during the luteal phase. Clinical case reports document patients who experienced monthly ulcers timed to hormonal shifts.16Journal Health of Indonesian. Management of Recurrent Aphthous Stomatitis (RAS) Cases Through a Communication, Information, and Education Approach The mechanism likely involves the effects of fluctuating estrogen and progesterone on the oral mucosa and immune signaling pathways.
That said, the relationship is more complicated than “hormones cause canker sores.” A Mendelian randomization study looking at whether estradiol levels causally drive mouth ulcers found no significant link in either men or women.17PubMed Central. Causal associations between estradiol and mouth ulcers: A Mendelian randomization study This does not mean the cyclical pattern women experience is imaginary. It likely means that hormonal fluctuations act as a modifying trigger in people who are already susceptible, rather than being a standalone cause. The practical implication is that if your canker sores track with your cycle, managing other triggers like stress, sleep, and nutrition during the premenstrual window might reduce their frequency.
When a Canker Sore Needs More Than Topical Treatment
Most canker sores are minor and heal within one to two weeks regardless of treatment. But a subset of people develop major aphthous ulcers, which are larger, deeper, and can last for weeks or even months. Others experience continuous overlapping episodes where new sores appear before old ones heal. For these severe cases, topical treatments alone often are not enough.
Systemic medications such as colchicine, pentoxifylline, and oral prednisolone are sometimes used, though the evidence for their effectiveness is debated.18PubMed Central. The treatment of chronic recurrent oral aphthous ulcers Stronger immunosuppressive drugs are generally reserved for canker sores associated with Behçet’s disease, a systemic inflammatory condition that causes ulcers in the mouth and elsewhere. The decision to move to systemic therapy usually comes after topical options have been thoroughly tried and found inadequate, and it involves weighing the side effects of ongoing immunosuppression against the burden of the ulcers themselves.
Any canker sore that persists beyond three weeks, grows unusually large, or is accompanied by fever, difficulty swallowing, or sores outside the mouth warrants a visit to a doctor or dentist. These features can signal something other than a simple canker sore, including conditions that mimic it, like oral lichen planus, herpes simplex (which causes cold sores, a different entity), or rarely, oral cancer. A sore that does not heal is always worth getting checked.
Mechanical Trauma and Braces
Physical injury to the lining of the mouth is one of the most straightforward canker sore triggers. Biting the inside of your cheek, jabbing yourself with a sharp chip, or having a rough edge on a tooth or dental appliance rub repeatedly against the tissue can all set one off. For people wearing braces, this is an ongoing issue, because brackets and wires create constant friction points.
Orthodontic wax, which patients press over irritating brackets, acts as a buffer between the hardware and the mucosa, reducing trauma and giving existing sores a chance to heal.19Journal of Dental Sciences. Comparison of microbial adhesion and biofilm formation on orthodontic wax materials; an in vitro study It is a low-tech solution, but an effective one. If you notice that your canker sores tend to appear at the same spot on your gum or cheek, check whether something sharp or rough in your mouth is repeatedly traumatizing that area. A dentist can smooth down a rough filling or tooth edge in minutes, and that single fix can end a pattern of recurring sores in that location.
Dentures, retainers, and even poorly fitting mouthguards can cause the same problem. The ulcers from mechanical trauma look and feel identical to stress-triggered canker sores, and they are. The immune and inflammatory response is the same; only the initial spark differs. Eliminating the source of trauma is usually all it takes.