An excerpt from Rabbi Kaplan's The Handbook of Jewish Thought.
Along with the wisdom to cure illness, God has given the physician permission to heal, as the Torah states in the case of bodily injury, "[The offender] must provide for his [victim's] complete cure" (Exodus 21:19) -- that is, by a doctor. Therefore the physician need not fear that he is usurping a prerogative of God, nor need he be apprehensive that he may injure of kill his patient, as long as he does his best.
A doctor who heals a patient fulfils the commandment, "You must return [your brother's loss] to him" (Deut. 22:2). If we are commanded to restore another's possessions, how much more so his life and health.
One should always seek the best possible medical help, but still pray to God for divine aid.
Although it is forbidden to rely upon miracles, one must realize that without God's help no physician can preserve life. It is thus written concerning Asa, king of Judah, "He became severely ill but even in his sickness, instead of beseeching God, he sought his physicians… and he died." (2 Chronicles 16:12). One should always seek the best possible medical help, but still pray to God for divine aid.
With the exception of the three cardinal sins, one must violate any religious law to save a life, as the Torah states, "Keep My decrees and laws, since a person can [truly] live only by keeping them" (Leviticus 18:5) -- live by keeping them and not die by keeping them.
Although keeping the Sabbath is considered a foundation of our religion, it may be violated in any manner necessary to save a life. In such a case, it is a meritorious deed to violate the Sabbath, and one who hesitates is guilty of bloodshed.
Where the Sabbath is violated in a case of danger, it must be done by responsible adults, and not by children or non-Jews, even where possible. However, if it is possible to avoid violating the Sabbath without causing any delay, it is permissible to do so.
Similarly, a dangerously sick or starving person may eat any forbidden food necessary to preserve his life. In such a case, all is permitted, even pork products, and bread on Passover.
Although Yom Kippur is our most sacred Day of Atonement, one whose life may be endangered by fasting is forbidden to do so. In such a case, one obtains atonement even without fasting.
In all cases of sickness or injury, we rely upon the opinion of a physician. As soon as he says that there is even a question of danger, religious law may be violated to preserve life, even if it is not certain that a given cure will help.
In any case where there is disagreement between medical authorities, one should make the same decision that one would make if no religious prohibition were involved, since where any question of danger is concerned, all religious laws must be [largely] ignored.
If the patient himself feels that his life is in danger, his word must be taken against any number of physicians. Regarding such a case, it is written, "The heart knows its own bitterness" (Proverbs 14:10).
One who goes against a physician's advice is held accountable for endangering his own life.
If any lay person claims to recognize a sickness or injury as being dangerous, his word must be taken, even if he is not certain, as long as he is not contradicted by a competent physician.
In any case, one should not violate religious law to provide a remedy unless it is prescribed by a physician or is otherwise known to be effective. Still, if the patient insists that a certain remedy is necessary, it may be administered for its psychological effect, as long as it is not known to be injurious to his health.
If a physician maintains that a certain remedy is necessary, he must be heeded even though the patient may insist that he has no need of it. In such a case, the patient may even be forced to take it. One who goes against his physician's advice and refuses to violate any religious law when required is considered among the foolishly pious. He is held accountable for endangering his own life. Regarding such a case, we are warned, "Do not be overly righteous" (Ecclesiastes 7:16).
When life is endangered, all religious laws may be totally disregarded. Therefore, even things that are not necessary to preserve the patient's life are permitted, as long as they enhance his well being. Nevertheless, one should not violate any religious law if treatment can be effected equally well without doing so. Similarly, one should violate the least serious law whenever possible, but when the danger is imminent and speed is essential, one need not concern oneself with these questions.
Even when danger is not imminent, religious law may be violated to prevent the risk of future danger. It is forbidden to hesitate in any case where such a delay may imperil life.
An internal injury is generally considered dangerous, and one may violate the Sabbath or any other law without question to obtain medical aid. However, even in the case of an extreme internal pain, one may not violate the Sabbath unless it may be a warning of a serous illness such as a heart attack or acute appendicitis.
Similarly, any injury to the teeth, gums or eyes is always considered dangerous. One may likewise violate the Sabbath in the case of any injury that might damage exposed blood vessels, as on the back of the hand or the feet, as well as any wound caused by a deadly weapon. In any case where there is danger of excessive bleeding or shock, immediate medical attention is required.
One may similarly violate the Sabbath to bring medical aid to a person suffering from a very high fever, as well as one bitten by a rabid don or other animal.
A woman in childbirth is considered to be in life danger.
A woman in childbirth is considered to be in danger unless the proper medical steps are taken. Therefore, she may be taken to the hospital, and medical aid may be summoned, as soon as labor commences, even on the Sabbath.
Similarly, a newborn child is considered to be in danger unless it receives the proper medical attention. Therefore, one may violate the Sabbath to do whatever is usually required for the infant.
If a woman dies in labor, the Sabbath may be violated in any manner to save her unborn child, as long as there is the slightest chance that it is still alive. As soon as the mother dies, the living child is considered to be born, lying in her body as in any other lifeless container. (If there is a chance that she is still alive, however, the mother may not be harmed in any way whatsoever even on a weekday.)
Where there is any question of saving life, the Sabbath may be violated in any manner necessary. Therefore, if a fire breaks out, it may be extinguished wherever life may be endangered. Similarly, if a building collapses, one may dig into the rubble to save the victims. Likewise, if a person falls into a well, or is in danger of drowning, all that is necessary may be done to save them. Even where a child locks himself into a room or closet where he may hurt himself or be dangerously frightened, the door may be broken down, or any help summoned.
Similarly, if a ship is in danger of sinking, or an individual is being pursued or attacked, the Sabbath may be violated in any way to save life.
In case of war, one may violate the Sabbath in any way to fight back, since many lives may be at stake.
One who violates the Sabbath in an attempt to save a life is worthy of merit even if it turns out that his services were not needed or in vain. Similarly, one who unintentionally saves a life while purposely violating the Sabbath is free of all blame.
One may violate the Sabbath where there is any chance, however miniscule, of saving a life. For example, one may search through the rubble of a collapsed building for survivors, even though the building may have been empty, or all the occupants killed, as long as there is any chance at all of a living person being trapped. Where life is at stake, we do not assume probabilities, since the commandment to "live by keeping them" does not permit any situation where observance should lead to death.
Similarly, the commandment to "live by keeping them" requires us to prolong life wherever possible, even temporarily. Therefore if someone is dying, or mortally injured, the Sabbath maybe violated to prolong his life even for minutes.
One may violate the Sabbath to save the life of a very young child or an imbecile, since the commandments apply to them, but they are exempt due to their lack of understanding. Similarly, one may violate the Sabbath to save an unborn fetus or embryo, since it will eventually live to keep many Sabbaths…
Restrictions on Violations
Where life is not endangered, one may not violate any Biblical prohibition, though one is ill or in pain.
If any part of the body is in danger of being permanently damaged without immediate attention, all rabbinical prohibitions may be violated to treat it, even though there is no mortal danger. Therefore, for example, it is permitted to set a broken or dislocated limb on the Sabbath. However, where a Biblical law must be violated, it may only be done by a non-Jew.
If one is sick enough to be bedridden, or in such pain as to feel sick all over, he may be treated by violating any rabbinical law on the Sabbath, as long as it is not done in the usual manner. Similarly, he may take any necessary medication or be treated by a non-Jew in any necessary manner. Therefore, for example, one who has a severe toothache on the Sabbath, may have it treated by a non-Jewish dentist.
One who has a simple ache or pain, or other minor illness, is forbidden to take any remedy on the Sabbath, even where there is no violation at all. All such cases are forbidden by rabbinical law, in order that one should not confuse them with cases of mortal danger and violate the Sabbath by preparing a remedy. Similarly, one may not be treated by a non-Jew, since rabbinical law forbids us from having a non-Jew do anything prohibited to a Jew, in order to preserve the sanctity of the Sabbath. God thus enjoins us through His prophet, "Refrain from pursuing your own affairs on My holy day…" (Isaiah 58:13). It is only in cases of extreme pain or illness that exceptions were made.
However, in a case where medicine is never used and there is no question of preparing a remedy, one may relieve pain on the Sabbath. Therefore, for example, one may remove a splinter, even with a needle, or press down a bruise with a knife or with ice.
It is forbidden to eat, or even swallow any forbidden food as a remedy when one is not dangerously sick. However, the Biblical prohibitions regarding forbidden foods only apply when they are eaten in an enjoyable manner, since this is the normal connotation of eating. When they are mixed with a very bitter substance, or eaten in any other manner which eliminates the possibility of deriving pleasure from them, they are forbidden only by rabbinical law, and may be eaten as a remedy, even when there is no danger.
It is permitted to swallow any forbidden food encased in an inedible capsule as a remedy, since it does not touch one's mouth or throat while being swallowed. Similarly, one may take a medicine made of forbidden foods which have been burned or chemically reduced, since they are no longer considered to be food.
Placing Oneself in Danger
We are commanded to preserve our health and well being, as the Torah states, "Take heed and guard your life very carefully" (Deut. 4:9), and "Guard your lives very carefully" (ibid. 4:15). It is therefore forbidden for a person to deliberately injure himself or endanger his life or health in any way. Torah law itself requires that we be more strict concerning a danger to our physical well being than concerning a violation of its own commandments.
One who places either his own or another's life in danger is guilty of violating the commandment, "Do not allow a dangerous situation to remain in your house" (Deut. 22:8). For this reason, one should keep his property clear of anything that might cause a serious accident.
It is an extremely serious sin to cause one's own death, whether by intent or negligence. One who does so is considered a murderer, as the Torah states, "I will surely demand an account for [spilling] your own life's blood" (Genesis 9:5).
From "The Handbook of Jewish Thought" (Vol. 2, Maznaim Publishing). Reprinted with permission.