Eating or drinking Shiurim on Tishe Beav

Question:

I’m sick in bed not feeling well this Tisha B’Av, and my doctor advised me to stay hydrated. I know it’s a fast day, but are there specific halachic guidelines for how I should drink in shiurim if I need to? How long should I wait between each drink, and does the timing differ between Yom Kippur and Tisha B’Av? I want to make sure I’m observing the fast properly while also taking care of my health.

Answer:

You may eat and drink as much as necessary, and in as many intervals as necessary, and you do not need to follow the Shiurim. In this regard, it is different than the law by Yom Kippur in which case one may only eat or drink if he a) contains a potential life-threatening illness or condition, and b) only in accordance with the Shiurim based on his health condition. The simple reason for the difference is that Yom Kippur contains a biblical fasting obligation under penalty of Kares, in contrast to Tisha b’Av which is only rabbinical.

Explanation:

A sick person is exempt from fasting all of the rabbinical fasts including Tisha b’Av. Now, since you write that you are not feeling well and your doctor has confirmed with you the need for hydration, then certainly you are under this exemption of fasting. With that said, the question is raised as to whether at the very least you should follow the Shiurim which we follow on Yom Kippur. Indeed, this matter is debated amongst the Poskim, and likewise amongst Chabad Rabbanim, with some equating it to Yom Kippur and saying that initially one should follow the Shiurim, and others contrasting it and saying that they do not need to be followed on Tisha b’Av. Indeed, in terms of the original rulings, Chabad sources such as the Tzemach Tzedek have taken the stringent approach. However, practically, the mainstream ruling that is followed in Horah even amongst Rabbeni Anash, with some exception, is to not require Shiurim.

Sources: See regarding a sick person fasting on Tisha b’Av: Michaber 554:6; Chayeh Adam 135:2; Kitzur SHU”A 124:7; M”B 554:11; Kaf Hachaim 554:33; Nitei Gavriel 65:12; See also: Rama 686:2 [regarding Taanis Esther]; Chayeh Adam 133:6; M”B 550:4; Kaf Hachaim 550:7 Stringent to require Shiurim: Tzemach Tzedek O.C. 108:110; Divrei Nechemia 42; Sefer Haminhagim p. 92 [English]; Halachos Ketanos 2:100; Maharam Shick 289; Shaiy Lamorah 4; Marcheshes 1:14; Biur Halacha 554 “Bemakom” in name of Pischeiy Olam; Lenient to not require Shiurim: Chida in Machazik Bracha, brought in Kaf Hachaim 554:31; Maharam Shick 290; Avnei Nezer 540; Aruch Hashulchan 554:7; Shevet Halevi 4:56; Kinyan Torah 1:118; Tzitz Eliezer 10:25-16; Shraga Hameir 1:59; Piskeiy Teshuvos 554:9; Hiskashrus 889 that so he received from several Rabbanei Anash, despite the ruling in Sefer Haminhagim ibid