What Not to Eat When Mouth Ulcers: A Guide to Soothing Your Canker Sores

December 10, 2025 •

4 min read

According to the National Health Service, mouth ulcers are common and usually clear up on their own within a week or two. However, navigating mealtime can be challenging and painful, which is why it’s crucial to know what not to eat when mouth ulcers appear to avoid further irritation and speed up recovery.

Quick Summary

This guide details the specific types of foods and beverages to avoid when you have mouth ulcers, including acidic, spicy, and rough-textured items. It also provides a comparison of irritating vs. soothing foods, and advice for dietary adjustments to manage discomfort and promote healing.

Key Points

Avoid Acidic Foods: High-acid items like citrus fruits and tomatoes can sting and irritate mouth ulcers, causing significant pain and prolonging healing.
Say No to Spicy and Salty Items: Spicy ingredients like chili and excessive salt can inflame oral tissues, increasing discomfort around the sore.
Steer Clear of Crunchy and Hard Textures: Abrasive foods such as chips, nuts, and crusty bread can physically damage the ulcer and hinder the healing process.
Choose Soothing Soft Foods: Opt for gentle, bland, and easy-to-chew foods like yogurt, mashed potatoes, and cool soups to get necessary nutrition without pain.
Adjust Drink Temperature and Content: Avoid very hot, acidic, or carbonated beverages. Instead, drink cool water or non-acidic juices through a straw to minimize contact with the sore.
Check Your Toothpaste: Some people find relief by using a toothpaste without Sodium Lauryl Sulphate (SLS), a common irritant for sensitive mouths.

Mouth ulcers, also known as canker sores, are painful, small lesions that can develop inside the mouth, on the tongue, or at the base of the gums. While they are not contagious and often heal naturally, certain dietary choices can significantly worsen the pain, prolong healing, and trigger new sores. Being mindful of what you eat is one of the most effective strategies for managing the discomfort and promoting a quicker recovery.

The Irritants: Foods and Drinks to Avoid

When dealing with a mouth ulcer, the goal is to reduce inflammation and avoid any mechanical or chemical irritation to the open sore. Certain categories of food and drink are notorious for causing problems.

Acidic and Citrus Foods

Acid is one of the biggest enemies of a mouth ulcer. High-acid foods cause a stinging sensation by further irritating the exposed nerve endings in the sore.

Citrus Fruits and Juices: Oranges, lemons, limes, and grapefruits contain high levels of citric acid. Consuming these, or their juices, can cause a painful burning sensation on the ulcer.
Tomatoes and Tomato-Based Products: Ketchup, marinara sauce, and salsa are highly acidic and should be avoided.
Vinegar-Based Foods: Pickled vegetables and other foods with a vinegar base can trigger a flare-up of pain.

Spicy Foods

Foods with significant heat or spice can inflame and irritate the delicate tissue around a mouth ulcer, increasing discomfort. The capsaicin found in chilies and other spicy components can feel like fire on an open sore.

Hot Sauces and Chilies: Any dish featuring hot peppers, including salsa and curries, should be avoided.
Strong Spices: Even milder spices like paprika can sometimes cause irritation for those with sensitive sores.

Crunchy, Rough, and Hard Foods

Physical abrasion is another key factor in delaying healing. Foods with a hard or rough texture can scrape and poke the ulcer, reopening the wound and increasing pain.

Chips, Pretzels, and Crackers: The sharp edges of these snacks can easily cause micro-trauma to the mouth lining.
Nuts and Seeds: While nutritious, their hard texture and small, sharp pieces can get caught in and injure the sore.
Crusty Breads and Toast: Abrasive textures like a toasted crust can be particularly painful to chew.

Salty and Sugary Foods

Both high-sodium and high-sugar items can affect mouth ulcers. High-salt content can pull moisture from the tissue and cause a painful sting. Excess sugar can potentially contribute to inflammation, though the evidence is more limited than for other irritants.

Salty Snacks: Avoid highly salted items like pretzels, potato chips, and salted nuts.
Processed and Sugary Foods: Some processed snacks and sugary treats can irritate sensitive oral tissues.

Hot and Stimulant Beverages

The temperature of your drinks matters just as much as your food. Extremely hot beverages can increase inflammation and discomfort. Stimulants like caffeine and alcohol can also exacerbate symptoms.

Hot Coffee and Tea: Always allow hot beverages to cool to a lukewarm or room temperature before drinking.
Alcohol and Carbonated Drinks: Both can be irritating. Alcohol can dry out the mouth, while carbonation and the acid in sodas can worsen pain.

Comparison of Irritating vs. Soothing Foods


Feature	Irritating Foods to Avoid	Soothing Food Alternatives
Acidity	Oranges, Lemons, Tomatoes	Bananas, Melons, Avocado
Texture	Chips, Nuts, Toast	Mashed Potatoes, Creamy Soups, Soft Noodles
Spice Level	Hot Sauce, Chili, Curry	Mild Seasonings, Herbs like Basil, Oregano
Salt Content	Pretzels, Salted Crackers	Unsalted Soft Foods, Tender Meats
Beverage	Coffee, Soda, Alcohol	Cool Water, Herbal Tea, Non-Acidic Juice

Promoting Healing and Comfort

Focusing on gentle, nourishing foods can significantly improve comfort and accelerate the healing process. Incorporate soft, bland, and cool options into your diet to provide essential nutrients without irritation.

Soft, easy-to-chew foods: Eggs (scrambled or boiled), yogurt, cottage cheese, and soft cheeses are excellent choices. Cooked vegetables that are soft and tender, like mashed potatoes, carrots, and sweet potatoes, are also very easy on the mouth.
Cool or lukewarm foods: Ice cream, popsicles, and cool soups can provide a soothing sensation. Just be aware that some people are sensitive to dairy.
Nutrient-dense options: Smoothies and shakes made with non-acidic fruits like bananas or melons, along with yogurt or a protein powder, can provide necessary vitamins and minerals when solid foods are difficult.
Moisture is key: Adding gravies, broths, and sauces can make drier foods like bread or chicken easier to swallow.

Beyond Diet: Other Steps for Relief

In addition to managing your diet, other lifestyle and oral hygiene adjustments can help alleviate discomfort and prevent future ulcers.

Use a soft-bristled toothbrush to avoid causing minor trauma to the mouth.
Consider using a toothpaste that does not contain Sodium Lauryl Sulphate (SLS), a foaming agent that can be an irritant for some people.
Rinse with a warm saltwater solution a few times a day to help with cleansing and healing.
Practice stress-reduction techniques, as stress and anxiety are known triggers for canker sores in some individuals.
Ensure you are getting enough vitamins, especially B-12, zinc, folate, and iron, as deficiencies can be a contributing factor.

Conclusion: Eating Smart for Fast Recovery

When dealing with mouth ulcers, the focus should be on reducing irritation and supporting the body's natural healing process through careful dietary choices. Avoiding acidic, spicy, salty, and rough-textured foods is paramount to minimizing pain and discomfort. By opting for soft, bland, and nutrient-rich alternatives, you can ensure proper nutrition while giving your mouth the gentle environment it needs to recover quickly. If ulcers persist or are unusually severe, consulting a dentist or doctor is recommended. Learning what not to eat when mouth ulcers arise is the first step toward a more comfortable and faster recovery.

For more detailed information on managing mouth sores, resources like the Cleveland Clinic offer expert medical insights on various treatment options beyond just dietary changes.

Frequently Asked Questions

Eating spicy food can significantly irritate and inflame a mouth ulcer, causing a burning sensation and increased pain. The capsaicin and other compounds in spices can hinder the healing process and worsen symptoms.

Yes, for some individuals, certain foods can be a trigger for mouth ulcers. Common culprits include acidic fruits like oranges and strawberries, nuts, chocolate, and foods to which a person may have a specific sensitivity.

Generally, dairy products like yogurt and milk are considered soothing because of their cool temperature and mild nature. However, some individuals with recurrent ulcers have a sensitivity to cow's milk protein and may need to avoid it.

Coffee should be avoided when you have a mouth ulcer, especially if it's hot. Coffee is acidic, and both the acid content and heat can irritate the sore and cause discomfort.

To get nutrients while avoiding irritants, focus on soft, nutrient-dense options like smoothies made with bananas, melons, and yogurt, well-cooked vegetables, soft proteins like eggs or tender fish, and fortified cereals.

Yes, rinsing with a warm saltwater solution can help cleanse the ulcer, reduce inflammation, and promote healing. It is a simple and effective home remedy.

Yes, while a mouth ulcer is present, it's best to avoid crunchy, rough foods like chips, nuts, and toast. The sharp edges can scrape the sore, cause pain, and potentially delay recovery.