Most mouth sores heal on their own within one to two weeks and don’t require medical treatment. What you can do in the meantime is manage pain, avoid irritating the sore further, and create conditions that help it heal faster. The right approach depends on what type of sore you’re dealing with.
Identify What Kind of Mouth Sore You Have
The two most common types are canker sores and cold sores (also called fever blisters), and they require different treatment. Canker sores appear inside the mouth as single, round white or yellow sores with a red border. They aren’t contagious and have no clearly established cause. Cold sores, on the other hand, appear outside the mouth, usually around the border of the lips, as clusters of small fluid-filled blisters. They’re caused by the herpes simplex virus (typically HSV-1) and are very contagious.
This distinction matters because canker sores respond well to over-the-counter numbing gels and antiseptic rinses, while cold sores are treated with prescription antiviral medications, either as topical creams or oral pills. If you’re treating the wrong type, you’re wasting time and money.
Home Remedies That Actually Help
A saltwater rinse is the simplest and most effective home treatment for canker sores and minor mouth irritations. Mix 1 teaspoon of salt into 8 ounces of warm water. If the sore is very tender, start with half a teaspoon of salt for the first day or two. Swish the solution around your mouth for 15 to 20 seconds, then spit it out. You can repeat this several times a day. Salt water helps reduce bacteria around the sore and draws out some of the fluid that causes swelling.
Beyond rinsing, avoid foods that will aggravate the sore. Spicy, acidic, and rough or crunchy foods can all irritate the wound and slow healing. Stick to softer foods and cooler temperatures while the sore is active. Drinking through a straw can help liquids bypass a sore on your lip or the front of your mouth.
Over-the-Counter Treatments
For canker sores, the most widely available OTC option is a topical gel or liquid containing 20% benzocaine, a numbing agent. To use it, dry the affected area first, then apply a small amount with a cotton swab or clean fingertip. The product forms a thin film over the sore that provides temporary pain relief. You can reapply up to four times a day. Children under two should not use benzocaine products, and children under twelve should be supervised.
Antiseptic mouth rinses sold over the counter can also help prevent infection at the sore site and may speed healing slightly. Look for rinses labeled for mouth sore relief rather than standard cosmetic mouthwashes, which often contain alcohol and can sting badly on open sores.
Prescription Options for Severe or Recurring Sores
If you get mouth sores frequently or they’re large and extremely painful, a doctor or dentist may prescribe a topical steroid. These work by calming the immune response in the tissue around the sore, which is often driven by overactive immune cells attacking the lining of the mouth. Reducing that inflammation relieves pain and can shorten healing time significantly.
For particularly bad flare-ups, some providers prescribe what’s informally called “magic mouthwash,” a compounded rinse that typically combines three ingredients in equal parts: an antihistamine that has mild numbing properties, a local anesthetic, and an antacid suspension that coats the mouth and helps the other ingredients stick to the tissue. You swish it around your mouth and spit it out. It’s designed for short-term pain relief rather than curing the sore itself.
Cold sores follow a different path entirely. Because they’re caused by a virus, antivirals are the standard prescription treatment. Starting antiviral medication early, ideally when you first feel the tingling that precedes a blister, can shorten an outbreak by a day or two.
Nutritional Gaps That Trigger Mouth Sores
Recurring canker sores are sometimes linked to nutritional deficiencies. The nutrients most commonly associated with mouth sore frequency are iron, vitamin B12, folic acid, and zinc. If you’re getting canker sores regularly and can’t identify an obvious trigger like stress or a mouth injury, it’s worth looking at your diet or asking your doctor to check your levels with a simple blood test. Correcting a deficiency can reduce how often sores come back.
Can Switching Toothpaste Help?
You may have heard that sodium lauryl sulfate (SLS), a foaming agent in most toothpastes, triggers canker sores in some people. The evidence is mixed. Some research suggests that toothpaste ingredients can irritate the mouth lining and stimulate sore formation in people who are already prone to them. However, a 2019 review found there wasn’t enough data to confirm that SLS-free toothpastes reduce ulcer frequency, duration, or pain. That said, if you notice your sores tend to appear shortly after brushing, trying an SLS-free toothpaste for a few weeks is low-risk and worth experimenting with.
When a Mouth Sore Needs Professional Attention
A sore that doesn’t heal within two to three weeks needs to be evaluated. The standard clinical guideline is that any oral lesion lasting longer than two to four weeks should be referred to a specialist for a definitive diagnosis. Most persistent sores turn out to be stubborn canker sores or result from chronic irritation (like a rough tooth edge rubbing the cheek), but a sore that won’t heal is also one of the earliest signs of oral cancer. This is especially important to take seriously if you use tobacco, drink heavily, or are over 40.
Other reasons to seek care sooner: a sore that’s unusually large (bigger than a pencil eraser), sores that keep coming back in clusters, a sore accompanied by high fever, or pain so severe that you can’t eat or drink enough to stay hydrated.