Question:
Is it permitted to use non-drinkable mouthwash on Yom Kippur morning if bad breath causes me significant distress, to the point that I dread Yom Kippur throughout the year because of it?
Answer:
Hello,
On Yom Kippur, this is not allowed. It is true it does cause you distress, and that is why there is room to be leneint on other fasts, (even Tisha B'av if it is really difficult for you), however not on Yom Kippur. There is a special mitzva that we have on this day, to "pain ourselves" and abstain from doing certain things, and in return Hashem is mochel our aveiros, and rips up evil decrees, in the merit of our teshuva and being uncomfortable on this day. Imagine if you would be offered, $5000 not to use mouthwash for 25 hours... the blessing that we get on this day is worth tons more than that.
Hashem should bless you with a good year, and everything that you need.
Sources:
M:B
