In various places throughout the Talmud, the sages offer medical advice. Thus we find in our tractate that our sages expound on the health value of eggs. Roasted eggs are singled out, preferably lightly roasted so that they are soft and swallowed as a thick liquid, but even fully roasted or boiled eggs (B. Berachot 44b, with Rashi). The medicinal value of other foods is also discussed. Spleen, for instance, is particularly beneficial for teeth, yet harmful to the intestines, therefore the sages recommend chewing it and then spitting it out. Leeks have the opposite effect - they are harmful to the teeth but beneficial for the intestines, so they should be cooked until soft and then swallowed without chewing. Raw vegetables eaten after bloodletting effect a pale countenance, nor should they be eaten on an empty stomach. Eating anything that has not attained a quarter of its potential size impedes growth. To restore vitality, one should eat things that were once alive, even small fish that have fully developed. Alternatively, meat that is located near the animal's throat also revitalizes the eater. Cabbage is good for sustenance, while beets should be eaten for healing. Cabbage can also help cure the ailing, as can a soup made from dry pennyroyal. Certain parts of animals are also noted for helping the sick - the innards, the womb and the diaphragm. Turnips are particularly bad for the stomach, unless their effect is weakened by cooking them together with fatty meat or drinking wine after they are eaten or they are overcooked. But beware: Small salted fish have fatal potential: if eaten on the seventh, 17th, 27th and perhaps also the 23rd day after being salted, they can cause death. This danger can be combated by fully roasting the fish or drinking beer after eating them. How are we to understand these health tips of the sages? Modern science does not subscribe to the majority of these guidelines. Should these health instructions be viewed as obligatory legal maxims akin to other authoritative statements of our venerable sages? Significantly, the great codifiers do not include these passages in their halachic works. Thus, for instance, the health guidelines offered by Maimonides (12th century, Cairo) in his great halachic compendium do not overlap with the talmudic sources. One commentator to Maimonides notes that medical advice is time and location specific (Rabbi Yosef Karo, 16th century, Safed). The talmudic health guidelines - and similarly those offered by Maimonides - were appropriate to the period and place where they were offered. Maimonides, therefore, did not follow the talmudic health guidelines, and we need not follow them, or for that matter Maimonides's suggestions, either. Maimonides himself seems to suggest this approach. The Mishna records an opinion that one who took a vow not to eat garlic until Shabbat must refrain from garlic only until Friday evening, because he intended that his vow should be in force only until the time that people customarily eat garlic, namely Friday evening (M. Nedarim 8:1). In his commentary to this Mishna, Maimonides notes that during the Second Temple period, it was customary to eat garlic on Friday evening because this would enhance male potency and Friday night was the recommended time for scholars to have conjugal relations (B. Bava Kama 82a). Significantly, Maimonides adds that garlic's therapeutic properties were effective "according to their diet and their land," implying that the curative powers of garlic in his time were different. In his philosophical writings, however, Maimonides goes further stating that talmudic science was lacking. Our sages advised their generation to the best of their abilities, but unlike their Torah knowledge, their medical knowledge was not based on a divine tradition (Guide 3:14). The idea that talmudic health advice is not legally binding predates Maimonides: The geonim of Babylon, who lived in the same region as the talmudic sages, recount a tradition that the talmudic health dicta do not have the status of obligatory mitzvot and should only be followed if they have been checked and approved by expert doctors. It should be noted that there have been scholars who recorded these medical instructions in their halachic compendia. Thus, for instance, Rabbi Shlomo Ganzfried (1804-1886, Hungary) in his abridged and accessible volume on Jewish law dedicates an entire section to health guidelines, drawing on Maimonides code without entertaining that they may no longer be relevant (Kitzur Shulhan Aruch 32). The majority of codifiers, however, were conscious of the limitations of rabbinic health guidelines. In many scenarios they acknowledge that health dicta were time and place specific, and suggest that human nature may have changed so that what was once healthy may nowadays be harmful (see Magen Avraham 173:1). Thus, for instance, our sages recommend eating salt after each meal to guarantee fresh breath during the day and protection from diphtheria at night (B. Berachot 40a). One prominent codifier quotes this passage and then adds that nowadays we do not have the custom of eating salt after a meal and we experience no detrimental affects, for human nature has changed (Rabbi Shneur Zalman of Lyady, today in Belarus, 18th-19th century). One modern commentator - Rabbi Avigdor Miller (1908-2001, US) - proposed that the temporary nature of medical opinion should impact our relationship with the Almighty. Successive generations of medical professionals discount and at times even mock the medical directives of previous generations. If past experience is any indication, even that which doctors advise today may in the future be disregarded. Nevertheless, the health directives of previous generations must have been effective in those times, otherwise they would have been quickly abandoned and ignored. Why did the Almighty create the world of medicine with fleeting truths? Rabbi Miller suggested that this situation leaves room for individuals to do all in their power to improve their health. Once the medicine takes effect, people then have free choice to acknowledge God's hand or to attribute their health solely to the medical counsel they received. The short-lived nature of medical truisms awakens us to the reality that the medicine is merely the vehicle through which the Almighty is the healer of all living things. The writer is on the faculty of Pardes Institute of Jewish Studies and is a rabbi in Tzur Hadassah.