Is it permitted to use mouthwash on a public fast day? Would a sensitive mouth, due to medical reasons be a good reason to be lenient?

(I can see it being less problematic than brushing one's teeth, because there's no fresh water being used, only the chemical mix that is mouthwash; that's not something you'd drink.)


2 Answers 2


Per Mishna Berura Orach Chaim 567:3:11 if a person is bothered by the lack of brushing their teeth or the smell/taste in their mouth, they are permitted to rinse their mouth on public fasts, however one should tip their head forward in order that it should not reach their throat.

  • 1
    Gershon, since the problem is "he may swallow it", I'm not sure how your answer covers Moshe's 2nd point, which should circumvent the issue.
    – YDK
    Commented Jan 5, 2012 at 17:23
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    This answer covers all points. It is allowed even for a non sensitive mouth. Commented Jan 5, 2012 at 19:20
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    The MB (who is referring to water) has 2 prerequisites: 1. He has "tzaar". 2. He tilts his head forward. (Note: The Aruch haShulchan only requires #2.) I think there is room in the case of mouthwash to negate both prerequisites since it is not an edible product.
    – YDK
    Commented Jan 5, 2012 at 20:33
  • @YDK, that sounds reasonable, but you need a source, which is what I think Moshe is looking for.
    – Seth J
    Commented Jan 6, 2012 at 1:31
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    ...."and on Yom Kippur one should be stringent in [not doing] this"
    – HodofHod
    Commented Sep 13, 2013 at 20:36

The accepted answer on this page covers fast days in general but is not specific to Yom Kippur. On Yom Kippur specifically, poskim prohibit using mouthwash.

dinonline writes (see original for sources)

It is permitted to rinse one’s mouth with mouthwash, with the exception of Yom Kippur, when it is prohibited.

R David Katz (author of Kesser Dovid: Halachic Guide To Dentistry) writes

The potential violation would be tasting on a fast day, but the Achronim tend to be meikel on fast days other than Yom Kippur

R Eliezer Melamed (author of Peninei Halacha) writes (see original for sources)

On Yom Kippur, however, when one must fast according to Torah law, one should not be lenient.

The only lenient opening I found was R Chaim Tabasky on yeshiva.co.il (here) but I don't understand it

One is not allowed to rinse one's mouth with water or mouthwash on Yom Kippur. However, if you will find it very uncomfortable to fast and pray, and you add something to the mouthwash to make its taste unpalatable, it is allowed.

Of course, consult your rabbi before implementing anything you learn here.

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