You've probably heard from a wise grandma or two that gargling with salt water can help cure a sore throat. But before you stand over the sink and put yourself through what feels like an open-mouthed dunk in the ocean, is the old salt water gargle remedy even legit?

The good news: Salt water actually does help alleviate the pain of a sore throat. “My kids know that gargling with salt water is the first thing I tell them to do when they have a sore throat,” says Sam Huh, MD, chief of otolaryngology at Mount Sinai Brooklyn.

The bad news: Salt water doesn’t cure a sore throat. The vast majority of sore throats are viral, not bacterial, Dr. Huh says, and they go away on their own in three to seven days. For the most part, your body has all the tools it needs to cure a sore throat. But it takes time, and you certainly don't want to sit around with a dry and painful throat while you wait for your body to work its magic. So, in the meantime, gargling salt water is one of the tricks that can help make sore throats a little less painful.

Let's get into the nitty-gritty details, so you can decide for yourself if a little salt water is just what you need for your throat pain.

Does gargling salt water kill bacteria in the throat?

“Salt water is hypertonic,” Dr. Huh says. That means that salt water has a higher osmotic pressure than the fluid in your cells. So when you submerge the cells in your throat in salt water, the liquid in your cells gets drawn to the surface and so does any virus or bacteria that are in your throat, meaning you might be able to spit some out along with the salt water.

“Extra moisture on the surface also makes a sore throat feel better,” Dr. Huh says. There’s also the potential that the salt could kill some of the bacteria or virus that’s causing your throat pain once its close enough to the surface. But, again, salt water isn’t a sore throat cure; it’s not going to attack the root source of your pain. It’ll just calm it down.

How much salt should you use to make a salt water gargle for a sore throat?

The salt content makes a pretty big difference. If you’re disgusted by the idea of swishing something so salty in your mouth, you might be tempted to put the teeniest bit of salt in your glass. Unfortunately, that won't do much for your throat.

“The water has to be hypertonic,” Dr. Huh says. “Think about how tears taste salty. It has to be saltier than that.” Typically, doctors recommend putting a quarter teaspoon of salt into a half cup of warm water. And yes, the water does have to be warm—for one, the heat helps dissolve the salt, but it also increases the blood flow in your throat which kicks your immune system into action.

The kind of salt you use doesn't matter. Any salt will work, as long as you use enough (though smaller granules may dissolve more quickly and easily).

How often should I gargle with salt water?

After your first salt water gargle, you should expect to start feeling better within 24 hours, Dr. Huh says. But you have to keep the routine up or else you’ll lose the sore throat-healing powers of the salt.

Depending on how much your throat hurts, he suggests gargling between two to four times each day. Just make sure you’re drinking plenty of water so the salt doesn’t dry out the rest of your cells, too.

Can everyone use a salt water gargle?

If you have high blood pressure, skip the salt water gargle. “Every time we gargle, we’re going to accidentally swallow some,” Dr. Huh says. That’s no big deal for people with normal blood pressure, but someone who has trouble controlling their blood pressure should stay away from the salt water and try something else instead.

Luckily, many of the home remedies we’re familiar with can help, because many of them are all about keeping your throat moist. “Personally, I believe chicken soup does the same thing as salt water, because it has a salty broth,” Dr. Huh says. He also likes that the soup has added nutrients that can fight infection.

Swallowing a spoonful of honey, using a humidifier, drinking lots of water and other liquids, and staying away from cigarette smoke are also sure to soothe your sore throat, he says. Looks like there is some validity to those grandma-approved remedies!