Most mouth sores heal on their own within 10 to 14 days, but the right combination of pain relief, rinses, and trigger avoidance can speed that timeline and reduce discomfort significantly. What works best depends on which type of sore you’re dealing with and how severe it is.
Figure Out Which Type You Have
The most common mouth sores are canker sores (aphthous ulcers), affecting about 20% of the population. They appear inside the mouth as white or yellow spots ringed in red. They’re not contagious, and their exact cause isn’t fully understood, though minor injuries like biting your cheek, acidic foods, stress, and certain vitamin deficiencies all play a role.
Cold sores are different. They appear on or around the lips, not inside the mouth, and are caused by a virus. They’re highly contagious and require antiviral treatment rather than the remedies that work for canker sores. If your sore is on the outside of your mouth, the strategies below won’t apply.
A less common possibility is oral lichen planus, which produces lacy white patches and sores inside the mouth. It’s an immune system condition that most often affects women over 50 and typically needs medical management.
Saltwater Rinses for Immediate Relief
A warm saltwater rinse is the simplest and most effective first step. Salt kills bacteria through osmosis, pulling water out of bacterial cells, and promotes wound healing by stimulating the cells responsible for tissue repair. Mix one teaspoon of salt into eight ounces of warm water and swish for 30 seconds, then spit. If the sting is too much, cut the salt to half a teaspoon for the first day or two. Repeat several times a day, especially after meals.
Over-the-Counter Pain Relief
Topical gels containing benzocaine (typically at a 20% concentration) numb the sore on contact and make eating and drinking bearable. Products marketed for mouth sores often combine benzocaine with menthol for a cooling effect and zinc chloride, which acts as an astringent to help dry and protect the sore. Apply a small amount directly to the ulcer with a clean finger or cotton swab. The numbing effect is temporary, usually lasting 20 to 30 minutes, so reapply as needed before meals.
Protective pastes that form a barrier over the sore can also help. These stick to the ulcer and shield it from food, drinks, and your teeth, which reduces both pain and irritation that slows healing.
Other Home Remedies Worth Trying
Honey applied directly to a canker sore may help with healing, though the evidence is modest. Studies on wound healing show a slight trend toward faster recovery with honey compared to standard care, but the difference isn’t statistically significant. Still, honey has natural antimicrobial properties and forms a soothing coating, so dabbing a small amount on the sore a few times a day is a low-risk option.
Baking soda rinses (one teaspoon in eight ounces of water) help neutralize acids in the mouth that can irritate open sores. Avoiding spicy, acidic, or crunchy foods while you have an active sore prevents the kind of repeated irritation that extends healing time. Tomatoes, citrus, chips, and anything with sharp edges are the usual culprits.
When Minor Sores Become Major Ones
Minor canker sores, the kind most people get, typically heal within 10 to 14 days without treatment. Major aphthous ulcers are larger, deeper, and can last up to a month. If you’re dealing with sores that are unusually large, extremely painful, or recurring frequently, a doctor can prescribe a steroid mouth rinse that reduces inflammation and accelerates healing. These rinses are swished around the mouth and spit out, delivering anti-inflammatory medication directly to the sore tissue.
Check for Nutritional Gaps
Recurrent canker sores sometimes signal a nutritional deficiency. Low levels of vitamin B12, folate, and iron are the most common culprits. In one study of 160 people with recurrent mouth ulcers, about 9% had low B12 levels at baseline. Folate deficiency was less common but still present. If you’re getting canker sores regularly, especially several times a year, it’s worth having your levels checked. Correcting a deficiency through diet or supplementation can reduce how often sores come back.
Good dietary sources of B12 include meat, fish, eggs, and fortified cereals. Folate is abundant in leafy greens, beans, and citrus. Iron comes from red meat, lentils, and spinach. If your diet is limited or plant-based, a daily multivitamin may help fill the gaps.
Switch Your Toothpaste
One of the most overlooked triggers for recurrent canker sores is sodium lauryl sulfate (SLS), a foaming agent in most conventional toothpastes. SLS can irritate the delicate lining of your mouth and make it more vulnerable to ulcers. The evidence here is surprisingly strong. In one study, participants who switched from an SLS-containing toothpaste to an SLS-free version saw a 64% drop in canker sore frequency, going from an average of 14.3 ulcers over three months to just 5.1. A 2019 systematic review of four clinical trials involving 124 participants confirmed the pattern: SLS-free toothpaste consistently reduced the number of ulcers, how long they lasted, and how much they hurt.
SLS-free toothpastes are widely available at most pharmacies and grocery stores. Check the ingredients list on your current tube. If sodium lauryl sulfate is listed and you get canker sores often, switching is one of the easiest changes you can make.
Signs a Mouth Sore Needs Medical Attention
Any mouth sore that hasn’t healed after two weeks deserves a professional evaluation. Oral cancer can look like a sore that simply won’t go away, a white or reddish patch, or a persistent lump. Other warning signs include loose teeth without an obvious cause, pain while swallowing or chewing, ear pain, and numbness in part of the mouth. A doctor or dentist will examine the area and, if anything looks abnormal, may take a small tissue sample to test. Early detection makes a significant difference in outcomes, so don’t write off a stubborn sore as “just a canker sore” if it lingers past that two-week mark.