1. a. A person who is not well (not because of the fast), even though his illness is not life threatening is absolved from fasting. There is no reason to be strict in this matter because the fast was not established for the ill.

b. If a sick person does not eat, he is in fact transgressing because he will cause himself to become weak and the Torah charges us to take care of our health, as it says ונשמרתם מאד לנפשתיכם, "you shall safeguard your souls” (Devarim 4:15).

c. In a case where it is questionable whether or not he is exempt from fasting a rabbi should be asked. One should not make such a decision himself. [The foregoing are general halachot and one should ask a rabbi when a halachic question arises.]

d. He may eat immediately in the morning, if necessary.

e. Although he may eat, he should not indulge so he can also participate with the community in mourning.

2. a. A person who is by nature weak or elderly and fasting is extremely difficult for him, he is absolved from fasting. However, a doctor should be consulted to determine if fasting would be harmful.

b. An individual who is very elderly and weak does not have to fast, even without asking a doctor.

3. If during the course of the fast one becomes ill, or feels weaker than is normal for one who is fasting – he may be considered in the category of a sick person. He should ask a rabbi to determine if he may break his fast.

4. A person who was exempt from fasting does not have to fast another day, when he feels better, in order to make up for the fast that he missed.

5. a. One who is not fasting does not recite the Aneinu prayer during Shemoneh Esrei, even at Shaharit when he has still not eaten.

b. A person who is not fasting may not be called to the Torah, even at Shaharit, even though he has still not eaten.

c. A non-fasting person who is a Kohen is not permitted to participate with the other Kohanim in Bircat Kohanim recited at Minchah. He must leave the Synagogue before Re’tzei.

6. a. A pregnant woman is absolved from fasting on the Seventeenth of Tamuz after the first trimester. 

b. If she is feeling weak or vomiting, even from the beginning of the pregnancy, then she does not have to fast because the fetus is at its weakest during that period and it could be dangerous for the mother and the fetus.

7. a. A woman who has given birth is absolved from fasting for the first two years of the baby’s life, whether she is nursing or not, because it takes that long to regain her previous vigor.

b. A woman who has suffered a miscarriage should ask a rabbi whether or not she is obligated to fast.

c. A pregnant or nursing mother who eats on the fast day should not indulge, so she can also participate with the community in mourning.

8. a. A “Katan – a child before bar or bat mitzvah – does not have to fast, even for a few hours.

b. If a child wants to fast the entire day, his parents should prohibit him/her from doing so.

c. Children who understand the significance of the fast should not indulge so they, too, can participate with the community in mourning.

9. a. When a Brit Milah is performed on a fast day which has been postponed it is permissible to be lenient with the father, the Sandak and the mohel not to complete the fast. That is to say that after praying Minchah Gedolah they are permitted to eat. This is only the case for a postponed fast, but if the fast falls on the appropriate date they are obligated to complete the fast.

b. Although they may eat they should not have a big meal as would be customary for a Brit held on non-fast day.

c. This applies only to a Brit that is made on the appropriate day (the eighth day). In the case of a postponed Brit they must complete the fast.

d. Regarding a Pidyon HaBen on a fast day the same leniency applies – the father and the Kohen do not have to complete the fast only if it is a postponed fast.

e. This law also applies to a groom and bride during the week of Sheva Berachot – they do not have to complete the fast if it is a postponed fast.