刮舌头比刷舌头更能去口臭，可舌头上的细菌也在帮你降血压

When you brush your teeth in the morning, do you scrape your tongue while you're at it?

In the last few years, tongue scraping has been getting more and more popular online.

A small metal strip bent into a U shape: put it at the back of your tongue, pull forward, and the white layer on your tongue gets scraped off.

That layer is called tongue coating; it holds bits of food, dead cells, and huge numbers of bacteria.

Tongue scraping is actually very old.

India's traditional medicine, Ayurveda, had a tongue-scraping habit long ago.

Now it has become a business, and it sells very well online.

So does it actually work?

Let's start with bad breath.

The main cause of bad breath is bacteria at the back of the tongue, which produce a sulfur gas called sulfur compounds that smells like rotten eggs.

In 2004, the University of São Paulo in Brazil ran a small experiment.

They asked 10 people to brush their tongues with a toothbrush first, and the gas dropped by 45%.

The same people then switched to a tongue-scraping tool, and the gas dropped by 75%.

The conclusion is simple: for bad breath, scraping works better than brushing.

However, the experiment had only 10 people.

In 2006, scholars put the relevant studies together in a systematic review, and found only 2 small studies.

Their view: tongue scraping helps with bad breath, but the effect is fairly short, and there isn't much evidence.

At this point, it seems we can conclude: if you want to fight bad breath, you can scrape.

But there's another side to this.

Not all the bacteria on your tongue are 'bad guys.'

Vegetables like spinach and beetroot contain lots of nitrate.

After you eat nitrate, part of it comes back into your mouth.

Some bacteria on your tongue can turn it into something else, which eventually becomes nitric oxide in your body.

Nitric oxide relaxes your blood vessels, so your blood pressure goes down a bit.

In other words, some of the bacteria on your tongue are actually helping lower your blood pressure.

So what happens if you kill them?

In 2019, a study asked 26 people to use a very strong antibacterial mouthwash called chlorhexidine twice a day.

After a week, their average blood pressure rose from 113 to 115.

Not a big number, but the direction is clear: kill off lots of mouth bacteria, and blood pressure goes up.

So does tongue scraping have the same problem?

The same study gave a reassuring answer.

People who scraped their tongues every day had a higher share of the 'helpful' bacteria.

The likely reason: scraping only removes the coating; it's a physical method that doesn't kill all the bacteria, and afterwards the useful bacteria grow back.

The researchers' suggestion: scraping your tongue plus eating more vegetables may be good for your blood pressure.

What you really need to be careful about is using strong antibacterial mouthwash every day.

So, back to the opening question: should you scrape your tongue?

If you care about bad breath, scraping does no harm, but don't expect it to last all day.

If your bad breath is always severe, it may be a tooth or stomach problem, and you should see a doctor.

Do you usually use mouthwash?

After hearing this, will you change how you do it?