Most people have swallowed salt water accidentally whilst at the beach or splashing in the sea. But have you ever thought about what salt water actually does to your body?
It’s useful to understand the science behind salt water’s effect on your body and to know the side effects of swallowing large amounts of it.
Whether you’re an outdoor enthusiast keen to know what to do if you accidentally drink salt water, or you’re prepping for an emergency when this may be the only type of water available to you – here’s what you need to know:
What happens to your body when you drink salt water?
Salt is made up of two key minerals: sodium and chloride. When you drink salt water, the cells in your body will take all these minerals in.
The salt content of sea water and ocean water is much higher than the content that can safely be processed by the human body. It is the high level of salt in these waters that make drinking salt water so dangerous.
When you drink salt water, your body responds with your kidneys trying to process the solution by making urine.
To make urine, the kidneys require water that has a lower salt content than sea water. In order to get rid of excess salt (after swallowing salt water), you would have to urinate out more liquid than you have consumed.
Salt water intake can induce vomiting in some people. Your body may also experience osmotic diarrhea due to the excess salt in the water.
These side effects of drinking salt water can quickly lead to dehydration which can cause death.
Many people underestimate the risks because we eat salt daily in our food – but this is usually done alongside drinking liquid which dilutes the salt and keeps our sodium levels healthy.

How much salt water is a dangerous amount to drink?
The average adult should not consume more than 2,300 milligrams of sodium per day – this is just under one teaspoon of standard table salt. For people with diabetes or heart/kidney diseases, this drops to 1,500 milligrams per day.
Ideally, you should not drink any salt water. In fact even one mouthful of salt water can be dangerous – especially if you are already dehydrated or if you have weak kidneys.
If you are in the sea and swallowed some salt water by accident, you may not feel any side effects immediately. Always try to spit out as much of the salt water as possible to avoid swallowing any unnecessarily.
You’ll quickly know if you have consumed too much salt water as you’ll begin to feel thirsty. This is a sign that you could be in danger – especially if you don’t have access to fresh water to help your body flush out the sea water.
Drinking any amount of salt water should be avoided if possible.
However, if you have accidentally consumed some, here’s what you should do to flush salt water out of your body.
What should you do if you have drunk salt water?

If you have drunk salt water, you’re very likely to become thirsty and potentially dehydrated very quickly. Within moments of drinking salt water, you may get diarrhea, which is a sign that you must act quickly.
The most important thing to do is rehydrate. You should not drink any more salt water – this is worse than not drinking any water so don’t be tempted into thinking that, as a liquid, it may be able to help you.
Rehydrate with clean, fresh water. This is the best way to counteract the effects of swallowing salt water and needs to be done as quickly as possible.
You may also have access to energy drinks or sachets to make up oral hydration solutions. These usually contain electrolytes with sugar, sodium and potassium to help with the effects of dehydration and diarrhea.
If you do become dehydrated or experience diarrhea from swallowing salt water, you must prioritize finding clean water or safe liquids to rehydrate with. This could involve simply returning to your base camp, asking for help from other hikers or in an extreme case, making an SOS call for a rescue or evacuation.
Will drinking salt water make you throw up?
Drinking salt water can make you throw up. In the past drinking salt water was used as a method of self induced vomiting to get rid of poison in the body.
Whether or not you throw up after drinking salt water will depend on two key factors:
- How much salt water you have drunk
- Your individual body’s reaction to the salt water
How do I clean up salty water so that it becomes potable?
There are a few different methods of cleaning up sea water to enable you to drink it.
Unfortunately most pre-made desalination systems are quite large and bulky, but don’t panic – there are methods you can use to make salt water potable with minimal equipment.
1. Thermal distillation
This is one of the most traditional ways of getting drinking water from salt water.
One of the main benefits of this method is that you can do it on a small scale and get your drinking water all in one go.
As well as desalinating the water, this process will also remove other impurities such as bacteria.
All you need for thermal distillation is:
- a smaller pan or cup to collect the purified water
- a heat source such as a camp fire or a portable gas stove
Put the salt water in the saucepan and then put the smaller pan in the middle.
Keep these both on the fire and cover the pan using the lid turned upside down. The water vapor produced when the water boiled will condense on the lid and drop into the vessel.
Top tip: you can speed up the condensation process by adding cold salt water onto the top of the lid.
2. Solar Distillation
Via this method, water vapor (without salt) is formed by the evaporation of water using solar heat. It is the same concept that nature uses to create precipitation from natural bodies of water.
Keeping equipment for solar distillation in your bug out bag can make the difference between life and death. A solar still can collect evaporation from the surface of the sea and make small amounts of drinking water in an emergency.
If you don’t have any equipment, you can even create your own solar still using a large plastic bottle, a heat source and a piece of cloth.
3. Forward Osmosis
This is a method that uses a highly concentrated salt solution (such as sugar syrup) to draw in water through an osmotic membrane.
Increasingly hydration bags, that use forward osmosis technology, are being used in survival kits, bug out bags and get home bags.Hydration bags offer an effective and quick way of separating large quantities of water using a semi permeable membrane.
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Conclusion
Although living cells depend on sodium chloride, It’s never advisable to swallow salt water.
If you swallow a small amount by accident, you should be fine as long as you keep yourself hydrated afterwards – this will help the body neutralize the effects of the salt water.
If you’re in an emergency situation without any alternative but to drink salt water, you’ll need to make sure you desalinate it first. If you go ahead and drink it without treating it first, you will get dehydrated and could become fatally ill very quickly.
Having some simple emergency equipment to enable you to use desalination methods could save your life.