Most mouth ulcers heal on their own within two weeks, but the right home treatments can cut pain significantly and speed up the process. These sores, commonly called canker sores, appear inside the mouth on the cheeks, lips, tongue, or gums as round white or yellow spots with a red border. They’re not the same as cold sores, which are fluid-filled blisters that form on the outside of the lips. What you’re dealing with inside your mouth is almost certainly a canker sore, and there are several effective ways to treat it.
Salt Water and Baking Soda Rinses
The simplest treatment you can start right now is a warm salt water rinse. Dissolve about half a teaspoon of salt in a cup of warm water and swish it around your mouth for 30 seconds, then spit. A 7 percent concentration of table salt has been shown to improve wound healing, and the rinse works by neutralizing the acidic environment inside your mouth that irritates the ulcer. You can do this several times a day, especially after meals.
Baking soda rinses work similarly. Mix one teaspoon of baking soda into half a cup of warm water and use it the same way. Some people also make a paste with a small amount of water and apply it directly to the sore, though this stings initially.
Over-the-Counter Pain Relief
Topical numbing gels containing benzocaine are widely available at pharmacies and provide fast, temporary pain relief. Apply the gel directly to the ulcer up to four times a day, and don’t use it for more than two consecutive days without checking with a doctor or dentist. These products aren’t recommended for children under two. The gel creates a numbing barrier over the sore, which is particularly helpful right before eating so you can get through a meal without wincing.
You can also find protective mouth rinses and adhesive patches designed to coat the ulcer and shield it from further irritation. These are especially useful if the sore is in a spot that constantly rubs against your teeth.
Honey as a Topical Treatment
Applying honey directly to a mouth ulcer is more than a folk remedy. A systematic review of 13 studies found that honey reduced the severity or duration of oral ulcers in 12 of them. For canker sores specifically, people who applied honey three times daily for five days reported improvements comparable to those using a standard prescription gel. For ulcers caused by denture friction, honey relieved symptoms and reduced pain faster than saline rinses alone. No adverse effects were reported in any of the studies. Use raw, unpasteurized honey and dab a small amount onto the sore after meals and before bed.
Prescription Treatments for Severe Ulcers
If your ulcer is large, extremely painful, or not responding to home care, a dentist or doctor can prescribe a corticosteroid dental paste. You press a small dab (about a quarter inch) onto the sore until a thin film forms, without rubbing it in. The best time to apply it is at bedtime so the medication stays in contact with the ulcer overnight. For more severe cases, you may need to apply it two or three times daily after meals.
Major canker sores, those larger than about one centimeter (roughly the size of a pea), can take months to heal and often leave scars. These warrant a visit to your dentist, who may also prescribe a medicated mouth rinse or oral medication to bring the inflammation under control.
Why You Keep Getting Them
If mouth ulcers are a recurring problem for you, the cause may be something you can change. One well-studied trigger is sodium lauryl sulfate (SLS), a foaming agent in most toothpastes. A systematic review found that switching to an SLS-free toothpaste significantly reduced the number of ulcers, the duration of each episode, the number of outbreaks, and the level of pain. Participants using SLS-free toothpaste developed roughly one fewer ulcer per outbreak and had episodes that were about two days shorter. Look for toothpaste labeled “SLS-free” at most pharmacies or health food stores.
Nutritional deficiencies are another common driver. In one study of people with recurrent mouth ulcers, over 50 percent were deficient in vitamin B12, and about 42 percent were anemic. Low iron and low folate levels also showed up frequently. If you get canker sores multiple times a year, it’s worth asking your doctor to check your B12, iron, and folate levels through a simple blood test. Correcting a deficiency can dramatically reduce how often sores appear.
Other common triggers include stress, hormonal changes, acidic or spicy foods, and minor mouth injuries from biting your cheek or aggressive brushing. Keeping a simple log of when ulcers appear can help you identify your personal triggers.
How Long Healing Takes
Minor canker sores, the most common type, are smaller than a centimeter across and typically heal within two weeks without scarring. Herpetiform canker sores, a rarer type that appears as clusters of tiny pinpoint ulcers, also heal within about two weeks. Major canker sores are the outlier: they’re larger, deeper, significantly more painful, and can persist for months.
Even with treatment, you won’t see overnight results. Most remedies reduce pain and shave a few days off the healing timeline rather than eliminating the sore instantly. The combination of salt water rinses, a topical treatment like honey or a numbing gel, and switching to an SLS-free toothpaste gives you the best shot at a faster recovery.
Signs a Mouth Ulcer Needs Medical Attention
A canker sore that lasts longer than two weeks is not normal and should be evaluated. The same goes for ulcers that come back two or three times a year or more, sores that are unusually large, or ulcers accompanied by a high fever.
Persistent or unusual mouth ulcers can sometimes be an early sign of a systemic condition. In Crohn’s disease, oral sores can actually appear before any digestive symptoms, often showing up as deep linear ulcers or cobblestone-textured patches in the cheeks. Behçet syndrome causes recurring, painful ulcers that tend to cluster on the soft palate. In pemphigus vulgaris, an autoimmune blistering disease, mouth ulcers are the first sign in 50 to 80 percent of cases and can precede skin symptoms by a year or more. These conditions are uncommon, but a sore that won’t heal or keeps coming back in unusual patterns is worth investigating.