In reply to your letter from the beginning of Elul in which you describe your health status, particularly with regard to your halitosis:

It is well known that according to our Torah, the Torah of Life, whenever there is anything concerning the body that needs to be improved, the improvement should be accomplished both in a physical as well as a spiritual manner.

With regard to the spiritual aspect: Be scrupulous in avoiding forbidden and uncalled for matters that relate to the mouth [and speech] and increase your permitted and laudable speech.

That is to say, avoid slanderous speech and idle chatter and [be more careful with regard to the kashrus of your] food and drink. With regard to the positive: Increase your words of Torah and prayer; increase as well your words of inspiration to others, strengthening them in their observance of Judaism — Torah and mitzvos.

The more particular you will be in increasing all the above, the more speedily you will heal [not only spiritually, but] physically as well. Also, seek the counsel of a medical specialist; see that he provides you with a proper diet and the proper medications, for it is entirely possible that your health issues result from a dysfunctional digestive tract. ...

(Igros Kodesh, Vol. II, p. 387)