When It is Medically Required to Eat or Drink on Yom Kippur


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by Rabbi Yair Hoffman for 5tjt.com

Sometimes, both the doctor and the Rav will tell a person not to fast on Yom Kippur.  Under such circumstances, one must reach out to one’s Posaik or Rav as to what to do.

For those who cannot reach their Rav, however, what follows are the emergency amounts that one may eat or drink- if it is absolutely necessary.  It is called “Eating less than the shiur” and – when medically necessary – is what is done on Yom Kippur.


There are actually two different prohibitions that are violated when a regular person eats on Yom Kippur.

  • The less commonly known prohibition is called “below the threshold prohibition” or the “Chatzi shiur prohibition.” Although this prohibition is a Torah one, it does not invoke the serious punishment of Karais. It is also set aside whenever there is anyone who is dangerously ill.
  • But what about the regular “above-the-food-threshold” prohibition? May a dangerously ill person violate this regular prohibition if he can be eating “below the threshold?” Although this issue is actually a debate , the consensus of opinion is that if it is completely feasible from a medical perspective, such a person should just eat and drink “below the threshold.”


What are the parameters of “below the threshold?” The parameters involve both time and food amounts. The “food amounts” are volume measures – not weight measures. And guess what? Food and drink are different – very different.


The food measurement is a constant –two thirds of a medium egg (see SA OC 618:7) – understood as one fluid ounce. The liquid measure varies according to each person. If it is determined that the patient should be fasting on Yom Kippur, then if feasible, the maximum quantity of food that may be eaten at one eating session is one fluid ounce – or 30 milliliters (ccs). It is a good idea to prepare these amounts in schnapps cups in advance. Proteins are, of course, more filling than starches.


The amount for liquids varies – depending upon the person’s individual cheek volume . Remember, it is not a mouthful, but rather a cheekful – one side of the mouth. For the average person one can figure 35 milliliters. For a small person it could be 30 milliliters.

All this refers to regular water. However, a few years before his passing (before Yom Kippur of 5769), Rav Elyashiv zatzal ruled that a person could actually use a different option – consuming water that has a Pagum (unnatural) taste that is not normally consumed because of its negative taste. The rationale for this ruling (based upon a Ramah) is that such drinking does not constitute a normal form of drinking and is thus only forbidden by Rabbinic ruling. The Rabbis, however, never made such enactments for people that are dangerously ill. More on this will follow in the next section.


There are some people who have some life-threatening illnesses that require the consumption of a very potent anti-biotic. These anti-biotics must be consumed with a significant amount of water. Because of this, the Pagum water suggestion of Rav Elyashiv zt”l would be the most appropriate approach to this dilemma.

But, what should be the recipe for such water? It should be distasteful enough that a normal person would not be drinking the water, yet not so distasteful as to cause the drinker to get sick or to violate the prohibition of bal teshaktzu – doing something disgusting.

One should always check with one’s doctor, but this author has experimented with various concoctions to create the Pagum-water. [Do not take the Pagum water if your doctor does not advise it for you.] The recipe that best fits the bill, in this author’s opinion, is a room temperature 16.9 ounce bottle of water, mixed with a half teaspoon of granulated onion powder and three shakes of salt. [The onion powder should first be dissolved in a small amount of hot water before Yom Kippur if possible. This will keep it as Pogum but will help reduce possible stomach unrest later.] If there is a negative reaction to the Pagum water, one can always go back to the “below the threshold” method.

Experiments conducted by this author have revealed the following revelation: The colder the water, the more onion powder and salt one can tolerate.


What is considered an eating or drinking session?


Ideally, one should try to space them every nine minutes.

  • The view of Rav Chaim Na-eh for food is 8 minutes (See Shiurei Torah 3:15).
  • Rav Moshe Feinstein zt”l writes (Igros Moshe OC IV #41) that b’dieved – in a case of need, they should have a gap of 4 minutes between them.


  • In regard to liquids one should shoot for a nine minute gap, but if not – a four minute gap.
  • If this is not possible, then, for liquids, one should try to fulfill the view of the Chasam Sofer (Responsa Volume VI #23) of a gap of at least two minutes.
  • The timing is based on the concept of the eating of a Pras – four eggs. The Mishna Brurah writes 618:20 that the shiur for this is nine minutes. These are the main views.


As discussed earlier, it is this author’s opinion that the material under discussion should be more widespread and made more available to others.


Whenever there is a doubt as to whether one is dangerously ill and there is no doctor or knowledgeable Rabbi that is present or available, one should , of course, feed the patient. We should all know the one-ounce food figure and then a nine minute gap formula and the four minute gap if this is not possible. It may also be worthwhile to have pre-filled one ounce food containers available for emergency situations too.

May Hashem, the Healer of all illness, grant us all a year of health, parnasah, and nachas from our families and ourselves.



The author may be reached at [email protected]