A salt water mouthwash is the simplest rinse there is, and it is one the NHS suggests for some everyday mouth problems. It costs almost nothing and takes a minute to make. Here is how to make it, how strong to make it, and when it is worth using.
How to make a salt water mouthwash
The NHS advice for mouth ulcers is to dissolve half a teaspoon of salt in a glass of warm water, rinse it around your mouth and then spit it out. Do not swallow it. You can repeat this as often as you like.
- Pour a glass of warm water. It should be comfortably warm, not hot.
- Stir in half a teaspoon of salt until it dissolves.
- Take a mouthful and rinse it gently around your mouth.
- Spit it out, and repeat until the glass is finished if you want to.
When a salt water rinse can help
Mouth ulcers
The NHS lists a salt water rinse among the things you can do yourself for mouth ulcers. A pharmacist can also recommend an antimicrobial or saline mouthwash, and the NHS suggests avoiding toothpaste containing sodium lauryl sulphate if you get ulcers.
After a tooth extraction
Dentists often recommend warm salt water rinses after a tooth is taken out, but the instructions vary, so follow what your own dentist tells you. As an example, University College London Hospitals advises starting 24 hours after the extraction, using two teaspoons of salt in a large cup of water that has cooled enough not to burn, and rinsing gently at least four times a day for about a week. That is stronger than the NHS ratio for ulcers because it is for a different purpose.
As a prescribed rinse
Salt water rinses are also used in dentistry. Scottish prescribing guidance for dentists includes a compound sodium chloride mouthwash, diluted with an equal amount of warm water, for adults and children.
Can you make an essential oil mouthwash at home?
We do not recommend it. We could not find any reliable guidance on safe amounts for a homemade essential oil mouthwash, and some essential oils are dangerous if swallowed. Tea tree oil in particular should never be swallowed: it has caused confusion, unsteadiness and even coma, and US poison centres handled more than 2,200 cases of exposure to it in 2022. Peppermint oil should not be used near the faces of babies and young children. If you want an essential oil mouthwash, use a ready made product and follow its label.
When to get advice
If a mouth problem does not clear up, keeps coming back or worries you, speak to a pharmacist or dentist rather than relying on home rinses.
For everyday freshness
A salt water rinse is good for soothing, but most people want something that tastes fresher for everyday use. No Fluo is a fluoride free and alcohol free mouthwash made with peppermint, tea tree, spearmint and lemon oils, made to be rinsed and spat out like any other mouthwash.
Safety: do not swallow. No Fluo contains tea tree oil, which is harmful if swallowed. Rinse and spit it out, and keep the bottle out of reach of children.
Frequently asked questions
What is the right salt to water ratio for a mouthwash?
For mouth ulcers, the NHS suggests half a teaspoon of salt in a glass of warm water. After a tooth extraction, follow your dentist’s instructions, as they may give a different strength.
How often can I use salt water mouthwash?
For mouth ulcers, the NHS says you can repeat a salt water rinse as often as you like. After an extraction, follow your dentist’s instructions.
Should I swallow salt water mouthwash?
No. Rinse it around your mouth and spit it out.
Does salt water kill bacteria in the mouth?
The NHS recommends salt water rinses for things like mouth ulcers rather than as an antibacterial mouthwash. For bad breath, the NHS suggests trying an antibacterial mouthwash or toothpaste.
Related guides
- How to use mouthwash correctly
- Tea tree mouthwash: and why tea tree oil must never be swallowed
- Natural mouthwash: No Fluo
- All guides