The saving of a life supercedes the observation of the Sabbath only in cases where there is a danger of death or a fear of such danger, but for all other illnesses, which do not constitute a danger of death, one is not permitted to violate the Sabbath. Moreover, one is forbidden to even take medication for these illnesses, though taking the medicine would not constitute a violation of the Sabbath; this is an ordinance of the sages.
The sages defined the illnesses which constitute a danger to life quite broadly; for any internal disease in the body one violates the Sabbath. Thus, for example, one who has fever (malaria) is considered to have an internal illness and one may violate the Sabbath for him. The scholars asked: What are the limbs or organs which establish the boundary between an internal illness for which one violates the Sabbath and an external illness, for which one does not? Answer: From the lips inward illness is considered internal. One of the scholars, Rabbi Eliezer, asked about toothache. What are the issues under debate? On one hand, teeth are inside the lips and so should be considered internal limbs for which one may violate the Sabbath. On the other hand, teeth are hard limbs which should be considered external and therefore one would not violate the Sabbath for them. One of the scholars, Abaye, answered that because the early sages (the Tana’aim) ruled that one who has a toothache should not gargle with vinegar as an analgesic against the pain, “One who is troubled with his teeth must not rinse them with vinegar.” One who is troubled is forbidden to gargle, but if he has strong sharp pains he may gargle with vinegar. Thus we see that teeth are considered internal limbs for which one may violate the Sabbath. The scholars rejected this proof, arguing that the early sages who said “one who is troubled” included in this group those with sharp toothaches as being forbidden to gargle with vinegar on the Sabbath. The scholars brought proof from a different sage, Rabbi Yochanan, that teeth are considered internal limbs for which one may violate the Sabbath. Rabbi Yochanan fell ill with scurvy (a Vitamin C deficiency which causes bleeding gums and the loss of teeth). He went to a gentile woman who was known as a healer. She gave him a prescription and prepared it for him. Rabbi Yochanan asked her how she prepared the remedy so that he could make some for himself on the Sabbath if the pains continued. The gentile healer told him that she was prepared to reveal the secret to him on condition that he did not reveal it to anyone else and that he swore to that effect. Rabbi Yochanan swore to the G-d of Israel he would not reveal it. The gentile woman told Rabbi Yochanan the medicinal remedy for his bleeding gums. On the next day, the Sabbath, during his speech to the congregants, Rabbi Yochanan revealed the secret remedy to all. How could he do this? He had, after all, sworn. Answer: He swore “To the G-d of Israel I will not reveal it,” meaning that he would not reveal the remedy to G-d, but that he would reveal it to the people of Israel, so he did not violate his promise. The scholars went on to ask: Would not this action cause a desecration of G-d’s name? The gentile woman, who does not understand the subtleties of the promise, will be angry and will conclude that the Jewish sages are liars who take advantage of strangers. Answer: Rabbi Yochanan, immediately after getting the detailed secret prescription, told her that he planned to tell her secret in the synagogue and explained to her the wording of his vow which would permit this. In any case, the scholars said, because Rabbi Yochanan used this medicine on the Sabbath to ease his toothache and bleeding gums (scurvy) we see that his teeth were considered internal limbs for which he was permitted to violate the Sabbath. The scholars rejected this proof, arguing that scurvy is a disease which begins with the gums and teeth and spreads to the digestive system, so it is considered an internal disease. But regular toothaches without bleeding gums are not considered as internal limbs but as external, and one does not violate the Sabbath for them. The scholars asked: What causes scurvy? Answer: Eating a cold wheat dish on cold winter days or a hot barley dish on hot summer days, or eating leftover flour-dipped fried fish. The scholars asked: What was the gentile healer’s secret remedy? Rabbi Yochanan had already revealed it, after all. Answer: She mixed a drink of hops with olive oil in salt. A different scholar, Mar son of Rav Ashi, said that the remedy was different; it was goose fat rubbed on the gums with a goose feather. Another scholar, Abaye, said that he tried both remedies and neither helped relieve his pain or bleeding. An Arab merchant told him to take pits of unripe olives, roast them in the fire upon a new hoe, and place them between his teeth. After he took the Arab’s suggestion he was cured of scurvy. The scholars continued to ask about the actions of Rabbi Yochanan, mentioned above. How could he have gone to ask advice of a gentile healer? Did not the early sages rule that one is forbidden to go to gentile healers and be cured by them lest the gentile healer kill the Jew? Answer: Since Rabbi Yochanan was an important and known man the gentile healer would not take the risk of killing him lest she be caught by the authorities, who forbid the murder of any person. The scholars went on to ask about an incident involving Rabbi Avihu who was an important person, but when he needed a remedy for his leg and went to an apostate healer, the healer spread a poisonous ointment on the leg and would have caused a need for amputation were he not saved by two of his students, Rav Ammi and Rav Assi, who cleaned off the poison with their mouths, allowing their teacher to heal. Answer: The gentile healer to whom Rabbi Yochanan went was a famous specialist, and a specialist will not endanger her reputation and so there is no fear she would kill a Jew. The scholars went on to ask: Rav Avihu’s healer was also a famous specialist yet he wanted to cause harm to his patient’s leg. Answer: Rabbi Avihu habitually argued with apostates and heretics, and his dealings with them caused them to hate him and wish to harm him, even at the cost of their “professional reputations” and specialties.
(Babylonian Talmud, Tractate Avodah Zarah 28a)