The following outline introduces the sections that deal with the questions: What may one do on Shabbos to treat someone who is sick? How should one respond if he encounters a person in a life-threatening situation?Our Sages established and defined general categories with which they identified different stages of illness, life-threatening situations, and the halachos applicable to each. These categories are as follows:

a) A person faced with a life-threatening illness or other life-threatening situation – In such an instance, “it is a mitzvah to desecrate the Shabbos for his sake.1 One who does so eagerly is praiseworthy, while one who asks [whether it is permitted to do so] sheds blood.”2 Even Scripturally forbidden labors may be performed by a Jew for the sake of a person in a life-threatening situation.

A person faced with an illness that is not immediately life-threatening, but could potentially become life-threatening if not treated, is considered as one with a life-threatening illness.3

If a person was in an actual or potentially life-threatening situation for which he received treatment, and that treatment stabilized his condition, it may be continued if the doctors fear that his condition could deteriorate should the treatment be discontinued.4

When there is a question about whether an illness is life-threatening, and whether or not the Shabbos should be desecrated, if possible, the sick person and a medical expert should be consulted. In case of doubt, the Shabbos should be desecrated.5

b) A person in danger of losing a limb – As long as there is no worry that the loss of the limb will lead to the loss of the person’s life, Scripturally forbidden labors may not be performed for his sake by a Jew. They, and of course, any Rabbinically forbidden activities may be performed for him by a non-Jew.6 Similarly, a Jew may perform any Rabbinically forbidden therapeutic treatment for such a person without deviating from the ordinary manner in which the treatment is administered.7

c) A person whose illness causes him to be bedridden, or who has a condition that causes him so much pain that his entire body is weakened as a result, but there is no danger to his life – Here too, Scripturally forbidden labors may not be performed for the patient’s sake by a Jew. They, and of course, any Rabbinically forbidden activities, may be performed for him by a non-Jew.8 Similarly, a Jew may perform any Rabbinically forbidden therapeutic activity for such a person, provided he deviates from the ordinary manner in which that activity is performed.9

d) A person who has an illness but is not bedridden, nor does he feel severe pain that weakens his entire body – It is forbidden even for a non-Jew to perform a Scripturally forbidden labor on his behalf.10 Shvusim11 may be performed for the patient by a non-Jew,12 but a Jew may only perform such acts if he deviates from the ordinary manner in which they are performed. It is also forbidden for the individual who is ill to eat foods that are obviously being taken as medications.13

e) A person who feels mere discomfort, but is otherwise healthy – It is forbidden to perform any therapeutic activity for him on Shabbos, even if it is performed by a non-Jew,14 except according to certain guidelines.15

If possible, one should avoid scheduling any extensive medical procedure (e.g., major surgery) on a Wednesday, Thursday, or Friday if it may lead to his being in a life-threatening situation on Shabbos, and as a result, Shabbos will have to be desecrated for his sake. For example, if in the days following the procedure, several examinations will need to be performed, some of them Scripturally prohibited. It is forbidden to initially enter a life-threatening situation three days before Shabbos if the patient knows the Shabbos will have to be violated as a result.16

Another reason to avoid scheduling elective surgery shortly before Shabbos involves the suffering and confusion of the patient and his family during the first days after the procedure.17