Canker sore home remedies: the salt water rinse and 6 more

A canker sore is a small round ulcer inside the mouth, white or yellowish with a red rim, and it is out of all proportion to its size. Eating becomes a negotiation, and so does talking.

It is not contagious, it is not a cold sore, and it heals by itself. French remedies aimed at the only realistic target: making the week tolerable.

Salt water, the one to actually do

Half a teaspoon of salt in about half a cup of warm water. Rinse gently for thirty seconds, three or four times a day, especially after meals.

It stings for a moment and then it soothes. It keeps the area clean, and it is the cheapest thing on this page by a wide margin.

A pinch of baking soda in the same glass makes it gentler, and works just as well.

Cold black tea

An old French remedy, and one with a plausible reason behind it.

Steep a black tea bag, let it cool completely, then hold it against the sore for two or three minutes. Repeat a few times a day.

Black tea contains tannins, which are astringent, and the cold itself dulls the pain. Whether it heals anything faster is unproven. It feels better, and that is worth something when you have not eaten properly in two days.

A dab of honey

Honey on a canker sore is one of those remedies that turns up in every tradition.

Apply a small amount with a clean finger or a cotton swab, three or four times a day, ideally after a rinse.

Never give honey to a child under one year old, in any form and for any reason. That is not about canker sores, it is about infant botulism, and it is absolute.

Aloe vera gel

A drop of pure aloe vera gel on the sore, two or three times a day. Cooling, and it forms a light film over an area that is raw.

Use a gel meant for the mouth, or pure gel from the plant. Not a sunburn preparation, which contains things that are not meant to be swallowed.

Coconut oil

A small amount of virgin coconut oil dabbed on the sore, a few times a day.

It coats, it soothes, and it tastes pleasant, which matters more than it sounds when your mouth hurts.

Plain yogurt

Not applied, eaten. A pot of plain unsweetened yogurt is cold, soft, requires no chewing, and does not sting.

There is a wider claim about yogurt and mouth ulcers that we are not going to make: the evidence is not there. What is true is that it is one of the few foods that goes down easily during a bad week.

What to avoid while it heals

This list matters more than several of the remedies.

• Lemon juice, vinegar, anything acidic applied directly. It is recommended constantly and it is a bad idea: it burns an open ulcer and does not speed anything.
• Citrus, tomato, pineapple, vinegar dressings. They will find the sore.
• Crisps, crusty bread, nuts. Sharp edges on an ulcer.
• Very hot food and drink.
• Anything that makes the mouth drier, which is also what feeds bad breath.
• Toothpaste containing sodium lauryl sulfate, which some people find clearly makes their mouth ulcers worse. Trying an SLS-free toothpaste for a few weeks costs nothing.

Why they turn up

Nobody knows completely, but the usual suspects are recognisable: a bitten cheek or a scraping toothbrush, a stressful stretch, tiredness, hormonal changes, and for some people a specific food.

Keeping a short note of what preceded each one is more useful than it sounds, because the trigger is often personal and consistent.

If yours arrive during pressured weeks, what helps stress is a more useful page than this one.

When to see a doctor or a dentist

Make an appointment if:

• the sore has not healed after three weeks
• it is unusually large, or there are several at once, repeatedly
• they come back constantly, more than three or four times a year
• you also have a fever, or you feel generally unwell
• eating and drinking have become genuinely difficult
• they appeared after starting a new medication
• a sore is on the lip rather than inside the mouth, which is more likely a cold sore and is a different thing entirely

Three weeks is the number to remember. A mouth ulcer that will not heal is one of the few things in this section that should never simply be waited out.

FAQ

What is the difference between a canker sore and a cold sore?

A canker sore is inside the mouth, is not contagious, and is not caused by a virus. A cold sore is on or around the lip, is caused by the herpes simplex virus, and is contagious. They are treated differently.

Does putting salt directly on a canker sore work?

No. Rinsing with salt water helps; a crystal of salt pressed onto an open ulcer simply hurts a great deal. The dilution is the point.

How long should a canker sore take to heal?

One to two weeks for an ordinary one. Past three weeks, it needs looking at.