Most canker sores heal on their own within 10 to 14 days, but the right treatments can reduce pain and speed that timeline. There’s no instant cure, but a combination of rinses, topical products, and dietary awareness can make a real difference in how quickly you recover and how often sores come back.
What a Canker Sore Actually Is
Canker sores are small, round ulcers that form inside the mouth, usually on the inner cheeks, lips, tongue, or soft palate. They typically appear as a single white or yellow sore with a red border. They are not contagious and are completely different from cold sores, which are caused by a virus and appear outside the mouth along the border of the lips as clusters of fluid-filled blisters.
The exact cause isn’t fully understood, but common triggers include minor mouth injuries (biting your cheek, aggressive brushing), stress, acidic or spicy foods, and hormonal changes. Nutrient deficiencies, particularly in vitamin B12, iron, and folate, are also linked to recurring mouth ulcers.
How Long They Take to Heal
Most canker sores are classified as minor, meaning they’re small and shallow. These typically heal within 10 to 14 days without scarring. Some very mild sores resolve in just two to three days with minimal pain.
Major canker sores are larger, deeper, and significantly more painful. These can take up to six weeks to heal and may leave a scar. If a sore hasn’t started improving after two weeks, that’s a signal worth paying attention to. Medical guidelines recommend that any oral lesion persisting for two weeks or longer after irritants are removed should be professionally evaluated.
Salt Water and Baking Soda Rinses
The simplest and most accessible treatment is a rinse you can make at home. Dissolve one teaspoon of baking soda in half a cup of warm water, swirl it around your mouth for 15 to 30 seconds, and spit. You can repeat this every few hours. The baking soda helps restore a more neutral pH in your mouth and may reduce inflammation around the sore. A basic salt water rinse works similarly: half a teaspoon of salt in a cup of warm water. Neither will sting as much as you’d expect, and both help keep the area clean so the sore can heal without complications.
Over-the-Counter Products That Help
Several OTC products contain active ingredients designed to numb the pain or protect the sore from further irritation. Look for products with benzocaine, which temporarily numbs the area, or hydrogen peroxide, which acts as an antiseptic. Brands like Orajel and Peroxyl are widely available and specifically marketed for mouth sores.
Protective pastes and gels that form a barrier over the sore can also help. These keep food, drinks, and your teeth from aggravating the ulcer while it heals. Applying these after meals and before bed tends to give the best relief.
Honey as a Natural Option
Honey has genuine evidence behind it for canker sores. Its antibacterial and anti-inflammatory properties make it effective at reducing sore pain, size, and redness. It also helps prevent secondary infection in the open ulcer. To use it, apply a small amount of honey directly to the sore four times daily. Raw honey works best. It won’t taste bad, but the key is reapplying consistently since saliva washes it away quickly.
What to Avoid While Healing
What you don’t do matters as much as what you do. Acidic foods like tomatoes, citrus fruits, and vinegar-based dressings will irritate the sore and slow healing. Spicy foods, crunchy chips, and crusty bread can physically aggravate the ulcer. Toothpaste containing sodium lauryl sulfate, a foaming agent, is a known trigger for some people. Switching to an SLS-free toothpaste during an outbreak (and potentially long-term) can reduce both pain and recurrence.
Avoid poking or prodding the sore with your tongue. It’s tempting, but repeated friction delays healing.
Preventing Canker Sores From Coming Back
If you get canker sores frequently, nutrient deficiencies are worth investigating. Low levels of vitamin B12, iron, and folate are all associated with recurring mouth ulcers. A blood test can identify deficiencies, and correcting them through diet or supplements often reduces how often sores appear. Good dietary sources include leafy greens for folate, red meat or fortified cereals for iron and B12, and eggs or dairy for B12.
Stress is another major trigger. People who notice sores appearing during high-pressure periods at work or school aren’t imagining the connection. Stress affects immune function in ways that make the mouth lining more vulnerable to ulceration. Managing stress won’t eliminate canker sores entirely, but it can reduce the frequency noticeably.
Use a soft-bristled toothbrush and be gentle around the gums and inner cheeks. Many canker sores start with a small injury from brushing too hard or from a sharp edge on a tooth or dental appliance. If a particular tooth or bracket is consistently irritating the same spot, dental wax or a visit to your dentist to smooth the edge can break the cycle.
When a Canker Sore Needs Professional Attention
A sore that lasts longer than two weeks, keeps growing, or comes with a fever warrants a visit to your doctor or dentist. Unusually large sores, sores that spread in clusters, or sores that make it genuinely difficult to eat or drink may need prescription-strength treatment, which can include stronger anti-inflammatory rinses or topical medications that your provider applies directly to the ulcer. Recurrent sores that appear many times a year could point to an underlying condition that’s worth investigating beyond simple home care.