Value Village ／ Health
This answer is a draft. It stays unpublished until legal review and source verification are complete.
Bad breath is hard to notice in yourself and awkward for others to mention. Since 2020, posts saying "I noticed my own breath behind a mask" have increased on forums abroad too. Here we look at why most causes lie in the mouth, and at the problem of worrying too much.
| Cause | Share / features | What to do |
|---|---|---|
| Tongue coating (the white film on the tongue) | The main source of bad breath. Bacteria break down food debris and protein into sulphur compounds | Once a day, gently, with a tongue brush (舌ブラシ, shita-burashi, sold at drugstores), from back to front (over-scrubbing damages taste and the lining) |
| Gum disease (periodontitis) | Signs in about half of adults. Inflamed gums and bacteria in periodontal pockets | Clean between the teeth (floss, interdental brush); cleaning and care at a dental clinic |
| Reduced saliva (dry mouth) | Saliva falls on waking, when hungry, when nervous, with age and as a side effect of medicines, and bacteria multiply | Water, chewing well at meals, chewing gum, breathing through the nose |
| Food, drink and tobacco | Garlic, spring onion, alcohol, cigarettes | Temporary. Reduced by water and brushing |
| Nose, throat and general illness | Sinusitis, tonsils, diabetes, kidney or liver disease (rare) | See a doctor |
| Stomach | Rare (gas does not normally rise from the oesophagus into the mouth) | — |
| Halitophobia | Worrying intensely about bad breath that is not there | Have an instrument-based breath test at a dental clinic for an objective check |
[Verify] Check the share of mouth-derived cases and the explanation of causes against materials from the Japan Dental Association and the Japanese Society for Breath Odor Research [日本口臭学会].
About 90% is in the mouth. Tongue coating and gum disease. The stomach is rarely the cause.
A toothbrush does not remove tongue coating or debris between the teeth. Tongue brush once a day; floss or an interdental brush.
It masks the smell for a while. Remove the cause first. Alcohol-based mouthwash dries the mouth and can make things worse.
Over-scrubbing damages taste and the lining. Gently, back to front, a few strokes, once a day.
Halitophobia (worrying intensely about bad breath you do not have) is a known condition. Get an objective breath test at a dental clinic. If there is gum disease, have it seen to; if not, that is reassurance.
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https://www.jda.or.jp/
http://jams-site.kenkyuukai.jp/
https://www.e-healthnet.mhlw.go.jp/information/teeth/h-02-001.html
⚠️ Editorial note: the source URLs above were identified by search. Our working environment cannot reach go.jp domains, so the contents have not been checked against the text. Verify every source before publication and record who checked it and when.
What we share here are ideas and everyday practices passed down among people living in Japan, together with general information drawn from public sources. They are not official recommendations, and they are not professional instruction. Practices vary between households and regions.
This is general information. Results vary from person to person and depend on your own conditions and surroundings.
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This article is not meant to diagnose or manage any specific medical condition. If you are worried about your health, see a doctor rather than relying on your own judgement.
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