Canker sores (aphthous ulcers) are small, painful open sores inside the mouth — typically white or yellow with a red border — that appear on the inner cheeks, lips, tongue, or gums and are not contagious. In most cases they heal on their own without any treatment: pain usually eases within 7 to 10 days and the sore fully heals within 1 to 3 weeks. There is no medicine that cures a canker sore, so the goal of treatment is to relieve pain and protect the sore while it heals. Over-the-counter numbing gels, rinses, and self-care are enough for most people; stronger prescription options exist for severe, frequent, or unusually long-lasting cases and should be chosen with a clinician.
Available without a prescription — follow each label.
Benzocaine topical gel/liquid (oral) Orajel, Kank-A, Anbesol Topical local anesthetic | Applied directly to the sore for temporary relief of canker-sore pain; this is the most common OTC active ingredient labeled for mouth/canker-sore pain. Per FDA, OTC benzocaine oral products carry a rare but serious risk of methemoglobinemia (a blood-oxygen disorder) and should not be used in children younger than 2 years. Follow the Drug Facts label, do not exceed the stated dose, and stop and seek care for pale/gray/blue skin, shortness of breath, or unusual tiredness. |
Mild antiseptic / antimicrobial mouthwash (alcohol-free) store-brand antiseptic rinse OTC oral antiseptic rinse | A gentle, alcohol-free rinse can help keep the sore clean and ease discomfort. Avoid strong alcohol-based mouthwashes, which sting and can irritate the ulcer. A simple salt-water rinse (about half a teaspoon of salt in a glass of warm water, swished and spit out) is a low-cost alternative recommended by NHS and MedlinePlus. |
OTC oral pain reliever (oral analgesic) Tylenol (acetaminophen), Advil/Motrin (ibuprofen) Oral analgesic / NSAID | Taken by mouth for overall mouth pain when a topical gel is not enough. Use only as directed on the Drug Facts label and follow that label's warnings (for example, ibuprofen cautions for stomach, kidney, or bleeding issues). Best for short-term pain control, not for healing the sore itself. |
A doctor may prescribe these — not for self-treatment.
Chlorhexidine gluconate oral rinse Antiseptic mouth rinse (prescription in the US) | A clinician may prescribe this antimicrobial rinse to help reduce discomfort and lower the chance of secondary infection while a sore heals. In the US it is prescription-only — do not self-start; use only under a dentist's or doctor's direction and follow their dosing. |
Topical or systemic corticosteroids Corticosteroid (anti-inflammatory) | For severe or recurrent canker sores, a clinician may prescribe a corticosteroid placed on the sore (paste, gel, or dissolving lozenge) or, rarely, a short course taken by mouth. These are clinician-prescribed only because dose, duration, and suitability depend on your health history; never self-start oral steroids. |
Amlexanox oral paste Topical anti-inflammatory (oral mucosa) | A prescription paste applied to individual sores that a doctor or dentist may use to help ease pain and may shorten healing of aphthous ulcers. Requires a prescription and professional guidance on how and when to apply it. |
Antibiotics or antivirals (only if an infection is diagnosed) Antibiotic / antiviral | Canker sores themselves are not caused by bacteria or the herpes virus, so they do not respond to antibiotics or antivirals. These are prescribed only when a doctor diagnoses a different or co-existing infection (for example, a cold sore, which is different from a canker sore). They require a clinician's diagnosis and prescription — never self-prescribe. |
Start with self-care, because most canker sores heal on their own: avoid hot, spicy, salty, or acidic foods and rough/crunchy items, use a soft toothbrush, and consider a toothpaste without sodium lauryl sulphate if you get frequent sores. For mild pain, a salt-water or gentle alcohol-free rinse plus a dab of OTC benzocaine gel directly on the sore is usually enough; add an oral pain reliever (acetaminophen or ibuprofen) only if needed and per its label. Choose by severity: occasional, small sores → self-care and OTC topicals; large, very painful, or slow-healing sores, or three or more outbreaks a year → see a dentist or doctor about prescription options (chlorhexidine rinse, corticosteroid paste, or amlexanox). Be honest with yourself about evidence: OTC remedies mainly relieve symptoms and do not dramatically shorten healing, so if a product does not help within a few days, it is reasonable to stop it rather than keep trying stronger home mixtures. Do not use OTC benzocaine in children under 2, and keep all oral products away from young children unless a clinician advises otherwise.
See a dentist or doctor (routine visit) if a mouth ulcer lasts longer than 2 to 3 weeks, is unusually large, keeps coming back (three or more times a year), or you get sores more often than seems normal — a sore that does not heal can rarely be a sign of mouth cancer and should be checked. Also seek care if the sore bleeds, keeps getting worse, or comes with other symptoms such as fever, a skin rash, diarrhea, joint pain, or sores elsewhere on the body, which can point to an underlying condition. Seek urgent or same-day care if you cannot eat or drink and are becoming dehydrated, if swelling makes swallowing or breathing difficult, or if you develop signs of a serious reaction to benzocaine (pale, gray, or blue-colored skin or lips, shortness of breath, rapid heartbeat, or unusual tiredness) — stop the product and get emergency help.
General reference, not medical advice, and not a substitute for your doctor or pharmacist. The right choice depends on your symptoms, health conditions, age, and other medicines — always read each label and confirm before taking anything.