Most minor mouth sores heal on their own within 7 to 10 days, but the right combination of rinses, topical treatments, and dietary changes can cut that timeline significantly. The goal is to reduce pain, protect the sore from further irritation, and create the best conditions for your mouth’s tissue to repair itself.
Start With a Saltwater or Baking Soda Rinse
The simplest and cheapest treatment is one you can make right now. Mix 1 teaspoon of salt into 8 ounces of warm water until it dissolves. Swish it around your mouth for 15 to 30 seconds, then spit it out. You can do this up to four times a day, plus after meals. If the rinse stings too much, drop down to half a teaspoon of salt.
A baking soda rinse works similarly: dissolve 1 teaspoon of baking soda in half a cup of warm water. This neutralizes acid in your mouth, which matters because an acidic environment slows healing and increases pain. You can alternate between salt and baking soda rinses throughout the day.
Use an OTC Numbing Gel
Over-the-counter gels, ointments, and sprays containing benzocaine provide direct pain relief by numbing the tissue around the sore. Apply to the affected area up to four times a day. The important limit: don’t use benzocaine products for more than two days without talking to a doctor, and don’t exceed four applications daily. Overuse increases the amount your body absorbs and raises the risk of a rare but serious blood condition.
Protective pastes that form a barrier over the sore can also help. They shield the ulcer from food, drinks, and your teeth, which reduces both pain and re-injury. Look for products marketed specifically as canker sore patches or protective oral pastes at your pharmacy.
Try Honey as a Topical Treatment
Applying honey directly to a mouth sore is a well-studied home remedy. In clinical trials comparing honey to standard prescription gel for canker sores, honey performed just as well for reducing ulcer size and pain when applied three times daily for five days. Participants also reported no side effects. Use a small dab of raw honey directly on the sore after meals and before bed, letting it sit as long as you can before eating or drinking.
Diluted Hydrogen Peroxide for Cleaning
Hydrogen peroxide helps clean the sore and clear away debris that can slow healing. Start with the standard 3% concentration you’ll find in a brown bottle at most drugstores, then mix equal parts peroxide and water to bring it down to 1.5%. Dab it onto the sore with a cotton swab or use it as a brief rinse. Don’t swallow it, and don’t use full-strength peroxide, which can irritate healthy tissue.
Avoid Foods That Slow Healing
What you don’t put in your mouth matters as much as what you apply to the sore. Acidic foods and drinks are the biggest offenders: citrus fruits, tomatoes, fizzy drinks, and alcohol all lower the pH in your mouth, which disrupts the protective layer of tissue and leaves the sore more exposed. Spicy foods and anything with sharp edges (chips, crusty bread, hard crackers) cause direct physical trauma to the ulcer and can restart the healing clock.
Stick with soft, cool, bland foods while the sore heals. Yogurt, smoothies, oatmeal, scrambled eggs, and mashed potatoes are all safe choices. Drinking through a straw can help liquids bypass the sore.
Switch to SLS-Free Toothpaste
Check the ingredients on your toothpaste for sodium lauryl sulfate, often listed as SLS. This is the foaming agent in most toothpastes, and it acts as a detergent that can irritate the lining of your mouth. One study found that switching to SLS-free toothpaste reduced the number, pain, and recurrence of mouth ulcers. If you get sores frequently, this single change is worth trying long-term. Several major brands sell SLS-free versions, usually labeled as “gentle” or “sensitive.”
Check for Nutritional Gaps
Recurrent mouth sores, especially ones that seem to appear without an obvious trigger like biting your cheek, can signal a nutritional deficiency. The three most common culprits are vitamin B12, folate, and iron. B12 deficiency is diagnosed when serum levels drop below 200 pg/ml, and folate deficiency when serum folate falls below 3 ng/ml. If you’re getting sores repeatedly, a simple blood test can identify whether low levels of these nutrients are contributing. Addressing the deficiency often reduces how often sores come back and how long they take to heal.
What a Dentist Can Do for Stubborn Sores
If you need a sore gone faster than home remedies allow, a dentist or doctor can apply silver nitrate to chemically cauterize the ulcer. This sounds intense, but it’s a quick in-office procedure. In a clinical trial, 60% of patients treated with silver nitrate had fully healed ulcers by day seven, compared to 32% in the control group. The average healing time after treatment was just 2.7 days, roughly half the time of untreated sores. No side effects were recorded in the study. The procedure also provides rapid pain relief.
Signs a Mouth Sore Needs Medical Attention
Any sore that lasts longer than 10 days needs to be evaluated by a dentist or doctor to rule out cancer or a precancerous change. This is true even if the sore isn’t particularly painful. A biopsy may be done for persistent sores without an obvious cause.
Seek more immediate evaluation if a mouth sore is accompanied by fever, blisters on the skin, eye inflammation, or a rash elsewhere on the body. These combinations can indicate a systemic condition rather than a simple canker sore. People with weakened immune systems, including those with HIV, can experience mouth sores that take weeks or even months to heal and should be monitored more closely.