A canker sore in your throat typically heals on its own within two weeks, but the location makes it especially painful and harder to treat than a sore on your lip or cheek. Because you can’t easily apply a gel or patch to the back of your throat, your best options center on medicated rinses, pain-relieving gargles, and avoiding foods that irritate the ulcer while it heals.
Why Canker Sores Form in the Throat
Canker sores (aphthous ulcers) can appear anywhere on the soft tissue inside your mouth, including the pharynx, the soft palate, and the back of the tongue. The two types most likely to show up in the throat are major aphthous ulcers, which tend to be larger than a centimeter and extremely painful, and herpetiform ulcers, which appear as clusters of tiny pinpoint sores.
The exact cause isn’t fully understood, but the process involves an overactive immune response where your body’s own inflammatory cells attack the lining tissue. Common triggers include physical trauma (a sharp piece of food scraping the throat, or irritation from hot foods), stress, hormonal shifts during menstruation, and nutritional deficiencies. Vitamin B12 deficiency is a well-documented trigger. In reported cases, patients with recurring canker sores had B12 levels roughly half the lower end of the normal range, and their ulcers resolved once the deficiency was corrected. Low iron and low folate have also been linked to recurrent outbreaks.
How to Relieve Pain Right Now
The throat is a hard-to-reach spot, so treatments that work as rinses or gargles are more practical than gels or patches. Start with a saltwater or baking soda rinse: dissolve one teaspoon of baking soda in half a cup of warm water and gargle gently several times a day. This helps reduce acidity around the sore and keeps the area clean.
For stronger relief, over-the-counter products containing benzocaine (sold under brand names like Anbesol) can numb the area temporarily. Look for spray formulations or products with long applicators, which are designed for sores in hard-to-reach spots. Mouthwashes containing hydrogen peroxide can also help cleanse the ulcer and may speed healing slightly. Menthol-based throat sprays offer another layer of pain and inflammation relief.
If over-the-counter options aren’t enough, a doctor can prescribe viscous lidocaine, a numbing oral rinse. For a sore throat, you gargle it and can swallow it. It should not be used more than once every three hours or more than eight doses in 24 hours. Because it numbs your throat, avoid eating for at least an hour after using it to reduce the risk of choking. Side effects like dizziness, confusion, or difficulty breathing are rare but require immediate medical attention.
Treatments That Speed Healing
Pain relief helps you get through the day, but certain treatments can actually shorten how long the sore lasts. Prescription steroid pastes or rinses are the most effective option. Corticosteroid pastes applied directly to ulcers reduce inflammation and promote faster tissue repair. For throat sores where a paste is impractical, a steroid mouthwash that you can gargle is a better fit.
Antibiotic mouthwashes also show meaningful results. In clinical trials, a chlortetracycline rinse increased pain-free days by 40% compared to placebo. A minocycline rinse performed even better for pain reduction. These are prescription products, so you’d need to ask your doctor or dentist about them if your sore is severe or slow to heal.
For people with frequent, severe outbreaks, doctors sometimes prescribe systemic medications like colchicine or low-dose oral steroids. These are reserved for cases where canker sores keep coming back and significantly affect quality of life.
What to Eat (and Avoid) While It Heals
Every swallow passes directly over a throat canker sore, so what you eat matters more than it would for a sore on your cheek. Avoid acidic foods like citrus fruits, tomatoes, and vinegar-based dressings. Spicy foods and anything with rough, sharp textures (chips, crusty bread, raw vegetables) will irritate the ulcer and can delay healing. Very hot foods and drinks also worsen inflammation.
Stick to soft, cool, or lukewarm foods: yogurt, smoothies, mashed potatoes, oatmeal, scrambled eggs, and broth-based soups that have cooled enough to be comfortable. Drinking through a straw can help liquids bypass the sore, though this depends on exactly where in your throat it’s located.
How Long Recovery Takes
Minor canker sores, the most common type, heal within about two weeks without scarring. Pain typically starts improving within a few days, even without treatment. Major aphthous ulcers are a different story. These larger sores can take weeks to months to fully heal and often leave scars. Herpetiform clusters, though they look alarming, usually resolve within about two weeks.
If you’re using a steroid rinse or antibiotic mouthwash, you can expect the healing timeline to compress noticeably. Most people find that active treatment cuts the worst of the pain down to a few days rather than a week or more.
When It Might Not Be a Canker Sore
A sore in the throat that hurts when you swallow can look and feel like several different conditions, and telling them apart matters because the treatments are completely different.
Strep throat causes a red, raw-looking throat with swollen tonsils, often with white patches or streaks of pus. It typically comes with fever, swollen lymph nodes in the front of your neck, and tiny red spots on the roof of your mouth. Canker sores don’t cause fever or swollen lymph nodes. If you have a cough, runny nose, or hoarseness alongside your sore throat, that points toward a viral infection rather than strep or a canker sore.
Canker sores are distinct, round or oval ulcers with a white or yellowish center and a red border. They’re not contagious. If you see blister-like clusters on the back of your throat accompanied by high fever, especially in a child, that’s more consistent with herpangina, a viral infection that requires different care.
Recurrent throat ulcers that keep returning deserve a closer look. Canker sores are a hallmark of Behçet’s disease, appearing in up to 99% of people with the condition. They also show up in about 60% of people with Crohn’s disease. If you’re getting throat ulcers frequently, or if they’re accompanied by other symptoms like genital sores, skin lesions, or digestive problems, bring this pattern to your doctor’s attention. A simple blood test can also check for the vitamin B12, iron, and folate deficiencies that drive many cases of recurring outbreaks.