Chapter 3. The Prohibition of Eating on a Fast

Tasting
21. Even tasting is forbidden, even if one will spit it out afterward. [20]
For Sephardim who follow the ruling of the Shulchan Aruch, tasting is permitted on condition that one spits it out. The Shulchan Aruch brings [21] two opinions as to whether the permitted tasting is only a small amount, up to the measure of a revi’it over the entire day, or whether even tasting a revi’it is permitted [even several times during the day, each tasting being a revi’it]; however, tasting more than a revi’it is forbidden, and the halachah follows this latter opinion. [22]

Rinsing the mouth
22. Rinsing the mouth is permitted only if one would suffer discomfort by not rinsing it; in that case, he must bend his head and mouth so that he will not swallow. [23]

Brushing teeth
23. Since after brushing one rinses the mouth, and rinsing the mouth is permitted only in a case of discomfort, one should therefore not brush teeth on a fast except in a case of discomfort [24] [or for the sake of human dignity]. Swallowing saliva is permitted. [25]

Medications
24. A healthy person, or someone with aches who takes medications: if they have no taste, it is permitted  to take them without water; if he cannot swallow them without water, or if the medication is sweetened, he should make it bitter by means of salt or several tea bags [chamomile] without sugar [whereas a sick person, even if not dangerously ill, who is exempt from the fast, takes them as usual]. [26]

If one forgot and ate
25. If one forgot and ate, even if he ate a kezayit or drank a cheekful of liquid, he is obligated to continue fasting, and he does not need to fast on another day; however, he should study the laws of fasting as atonement for his sin. [27]

Reciting Aneinu for one who forgot and ate
26. If one forgot and ate: if he ate less than a kezayit or drank less than a cheekful, he says Aneinu as usual. But if he ate more than a kezayit [and some say: more than the measure of a kothevet] or drank more than a cheekful, since his law is that he must continue fasting, he says Aneinu, but should say “on this fast day” instead of “the day of our fast.” [28]

Regarding a sick person
27. A sick person who is permitted to eat does not say Aneinu; likewise, a minor who is not fasting does not say Aneinu. [29]

Smoking cigarettes
28. Smoking an electronic cigarette is forbidden. Smoking regular cigarettes was permitted privately for someone for whom this is extremely difficult (however, one must be careful regarding cigarettes throughout the year as well). [30]

Washing and anointing
29. Washing and anointing are permitted on a fast. [31]

Washing the entire body
30. The washing that we said is permitted is either washing one’s face, hands, and feet with hot water, or one’s entire body with cold water; however, regarding washing the entire body with hot water, the custom is to be stringent. [32]

A pious person regarding washing and anointing
31. A pious person should be stringent regarding washing, not to wash at all on a fast, not even with cold water, and should likewise be stringent regarding anointing. [33]

Wearing leather shoes
32. Regarding wearing leather shoes: when walking in the street, even a pious person should not be stringent in this matter, because it is something done in public and appears as arrogance and as mockery and ridicule; however, at home a pious person should be stringent not to walk in leather shoes, as on Tishah B’Av. [34]

Marital relations
33. It is proper for a pious person to be stringent regarding marital relations also on the night before the fast, unless that is the night of immersion. [35]

[20] Shulchan Aruch (siman 567, se’if 1).
[21] Ibid. (se’if 2).
[22] Mishnah Berurah (ad loc., se’if katan 8) and Sha’ar HaTziyun (se’if katan 6).
[23] Shulchan Aruch (siman 567, se’if 3), Mishnah Berurah (se’if katan 11).
[24] Mishnah Berurah (siman 567, se’if katan 11).
[25] Mishnah Berurah (siman 567, se’if katan 13).
[26] Shulchan Aruch (siman 612, se’if 6).
[27] Shulchan Aruch (siman 568, se’if 1).
[28] Shulchan Aruch (siman 568, se’if 1), Mishnah Berurah (se’if katan 3), and Shulchan Aruch (siman 565, se’if 1).
[29] Shulchan Aruch (siman 565, se’if 1) and Biur Halachah (ad loc.).
[30] Mishnah Berurah (siman 555, se’if katan 8).
[31] Shulchan Aruch (siman 550, se’if 2).
[32] Sha’ar HaTziyun (siman 550, se’if katan 8).
[33] Mishnah Berurah (siman 550, se’if katan 6).
[34] Ibid.
[35] Mishnah Berurah (siman 550, se’if katan 6).